This may be backwards thinking for a UL forum but I like to keep at least 1 solo double wall shelter in my gear closet. I have a Tarptent Moment and like it but prefer a double wall for some situations. Over the past summer I used a Seedhouse SL1 for extended periods and it was ok but I don't like the front entry that can get gear and the inside tent wet and the 11 stakes needed to make a "freestanding" tent stable. I did consider a TT Rainbow but it would still come in close to 40oz sealed with the inner liner.
The MSR Hubba is on sale right now for $182 and it is tempting. Side entry, rectangular floor area, less stakes, double wall, and true freestanding compared to the SL1. But, it does weigh nearly 1/2lb more than the SL1. I have also heard that the Hubba series can take a little more harsh weather than the Seedhouse SL series. Materials of the Hubba seem a little more beefy, maybe that is worth it for my "when all else fails" tent. I read that the floor is very waterproof, rated 10,000mm. The vestibule is much roomier and gear would not be in the way during entry or exit.
Maybe I would be better off getting a TT Scarp 1 with all the options but that would be $420. The tent would probably be used for some sections of a thru-hike and light winter weather. Sometime in the future I am interested in trying an MLD Duomid with solo net tent.