Note: This review is for the formerly offered Seedhouse 1 tent from Big Agnes and not the current offering of Seedhouse SL1. However, because of the similarities between my tent and the current offering, I feel much of what I will report here to still be pertinent.
I have 4+ seasons with the Seedhouse 1 (2009 version), and can definitively give an educated personal review. As mentioned, this is an earlier version of the Seedhouse line, and not a Super- or Ultra-light version. Weight is the major difference in the tent I have (see images for weight) and the currently offered version of the Seedhouse SL1 (2 lb 9 oz). The form, fit, and function of the tents remain very similar (if not the same). With solo backpacking tents I consider the following important: Shelter, Packable size, Weight, Room, Strength & Durability and Ease of Use, with more or less that order of importance. I will grade this tent within those categories on a scale of 1 to 5 with 5 being superior quality. With those scores an overall final score (out of 30) and a letter grade will be given. There are obviously more areas in which a tent can be graded, but for me it is important to compare apples to apples. In other words this tent will have a different use and features than say a tent used for the whole family within car accessible campsites. The form, fit, and function of this tent is obviously for 1 person on something akin to backpacking trip. The grading therefore will correlate to how it fulfills that role. One man solo shelters are a specific breed and can only be compared to each other. While some may prefer bivy sacs or a tarp, I enjoy the solidarity of a tent. With that preamble aside here is my review:
Shelter (4.5)
When you backpack frequently, you fine tune your gear to eventually include the top of the line equipment. It is not uncommon for a backpacker to have a 300 dollar down sleeping bag. Such a bag cannot get wet; therefore, your tent must keep moisture out either from rain or condensation. For this category, this tent is awesome. The smallness of this tent requires you to stake it out as taut as possible so as to be able to access the most room. When this is done, the tent is very strong, and well ventilated. I have experienced high winds and heavy rains within this tent, and came away as dry as my favorite jokes. One note of observation, when camping in a spot with a common wind direction, it is best to place the door facing the wind. I knock it down a half a point because the single pole running the length of the tent is not very sturdy without the use of the fly or without it fully staked, but that is nitpicking. This tent employs 1200 mm polyurethane coating and the floor is 1500 mm coating.
Packable Size (4, 4.5)
The listed size on the website at the time of purchase for my tent was 19 inches long by 6 inches in diameter (4). The new Seedhouse SL 1 has the listed dimensions of 17 inches long by 4 inches in diameter (4.5). I have found this to be the size of the bag, and not necessarily the size of what you pack it to. In other words, if you pack it tight you can get it so the limiting factor is the length of the broken down pole. I always place the footprint in the same bag with the tent, and it all fits really well. For volume saving possibility I have also at times placed everything but the poles in a compression sack and got the volume much smaller. However, good rolling and folding should be done before applying this technique as the Polyurethane coating has a bending/folding fatigue life.

Shown here with most minimalistic volume configuration possible. Camera lense cap for size reference.
Weight (2.5, 4.5)
The listed weight of my tent at the time of purchase was 3 pounds 4 ounces, but that was without the footprint. The listed weight for the Seedhouse SL1 version is 2 pounds 9 ounces and with the footprint (4 ounces) is still under 3 Pounds. I would categorize the current offering of the SL1 as great (4.5). Weighing the items separately on my tent I obtained the following information. The tent, fly and footprint inside a compression sack totalled 2 Pounds 15 ounces, the stakes were 6 ounces, and the pole itself was 11 ounces. This totals almost exactly 5 Pounds. Not great, in fact poor (2.5). This of course is not much when considering the overall weight of the backpack, but for a one man tent, it is really poor. I can understand why Big Agnes went to a Super Light version in this tent. The current version is much closer to the realm of what a solo person backpacking tent should be. The fast fly weight is well under 2 pounds and would basically do the same thing that people do with tarps. I have yet to test the fast fly version of my setup as I am usually within forests during months when mosquitoes and other annoying insects are a problem.
Room (4.5)
Now of course giving this category a perfect score might seem impossible, but this tent scored close to perfect given it’s comparison it to other 1-person-tents. I have developed a simple scoring methodology to compare it to three other “Free Standing” one-person-tents within the same price range. Just adding three variables (Sit room height, floor area, vestibule area) together gives a score. The higher the score the better. I have never felt clostrophobic in the Seedhouse 1, and when it is stretched taut, I could almost argue that another small person (i.e. toddler) could also fit beside me for the night (I have yet to test this idea, but look forward to the opportunity). For this category, the current Seedhouse SL1 version has the exact same dimensions as my tent.
BA Seedhouse SL1: Sit room = 38 inches, Floor space = 22 square feet,Vestibule Space = 5 square feet; Total for Seedhouse = 65 (2 lb 9 0z)
MSR Hubba NX Solo: Sit room = 36 inches, Floor space = 18 square feet,Vestibule Space = 9 square feet; Total for MSR = 63 (2 lb 14 oz)
Alps Mountaineering Lynx 1: Sit room = 36 inches, Floor space = 20 square feet,Vestibule Space = 10 square feet; Total for Lynx 1 = 66 (3 lb 15 oz)
Nemo OBI 1P: Sit room = 40 inches, Floor space = 21 square feet,Vestibule Space = 9 square feet; Total for OBI 1P = 70 (3 lb 3 oz)

Much more room in fast fly mode (ala tarp). Insects and critters are also allowed admittance. Yes, I know my boy is cute.
Strength & Durability (5)
Through 4+ seasons of use and multiple weather conditions, I would easily consider this a durable tent. I would not however use this tent much without the footprint. For me 1500mm is not enough protection for me to leave the footprint home. The quality of durability I see sometimes to be a tradeoff with weight. I can attest to the durability of the aluminum poles under the load of wrestling toddlers too. I have been careful with this tent, but normal use has not caused a rip, tear, or any other sort of undesired characteristic to develop. The use of 7000 series aluminum for the tent pole is nothing special, but they do claim to have a environmentally friendly anodizing process for the poles, so I guess that is good. As I mentioned, when this tent is fully staked, and taut, it is very sturdy.
Ease of Use (4)
Set up and take down is very easy and quick. Pulling it taut in all possible directions is also intuitive and quickly realized. The clip system and one pole design does not allow for this tent to be setup incorrectly, so that is also good.
One item of mention for this section is the entering and exiting technique required for this tent. The D shaped door and the limited moving room within the tent for me have required a feet first entry into the tent most times, and at some times entry into your sleeping bag at the same time. Changing clothes within the tent is difficult, as I would assume be the case with all one-person-tents. When changing clothes in the tent, most of it is done on your back. If this is done during a cold morning, or after a long day of hiking when cramping is possible, this tent is not the best.
Conclusion
Overall, I am pleased with my tent and give it a score of 25 out of 30 or a solid B. The area of highest concern (weight) is what they improved the most with the current offering of the Seedhouse SL1. It accordingly scores a 27 out of 30 or an A-. For the pricepoint, I see the Seedhouse SL1 as a good purchase for those that don’t want to spend hundreds of dollars more to only shave a few ounces. Admittingly I have always been a fan of Big Agnes, but I am a less loyal customer of their tents because there are so many high quality producing tent companies out there. However, that being said, were I given the opportunity to buy a similar tent from Big Agnes in the future, I wouldn’t hesitate. One-person-tents are a rare breed because they really have to be highly optimized to justify purchasing them over 2-person-tents or just using a tarp or a bivy. However, if they are optimized, and they are free standing like the Seedhouse SL1, I find them a good purchase. Thanks for reading.