So, today my Lightheart Solo in cuben fiber arrived.
The first thing I did was put it on my scale: 1 lb 3.5 oz. Weight included everything but stakes.
Next, took it out in the yard with the instruction sheet to see how difficult it would be to setup. Time from taking out of stuff sack to having it setup in a way that I would feel comfortable sleeping in it: 5 minutes, 50 seconds. Next time I would guess it would take roughly half that, assuming good site selection.
Next, check out the room inside the tent: It's a diamond shape - not quite as much room on the ends as the TT Rainbow but there is very clearly more than enough room for me and my gear with plenty left over. This tent would be an awesome choice for someone over 6'3"... Very important to me is the ability to sit up inside the tent without hitting the roof - no problem there.
Vestibule is not huge but perfect for a pair of boots with room to cook. I got a door on the other side so I could access the vestibule on the other side as well and use that space. I recommend this addition if you order a Solo.
Cons: Nothing jumps out at me as far as design goes. The cuben fiber material feels like it is more fragile than regular silnylon but that may not be true in practice - we'll see. I did get the silynylon floor so I'm not terribly worried about floor punctures based on my previous tent experience (never use a ground sheet, never had a problem).
Overall impression: Pretty darned good - some serious "Wow factor" on the weight - hard to believe I was holding a double walled tent with all that room at less than 20 ozs.
I'm going to hike Devil's Fork Gap to Hot Springs again this weekend (or maybe Iron Mt. Gap back to Erwin...) and do an overnighter in it. There's a good chance of rain this weekend - I'd really love to experience a torrential downpour with high winds while I'm out.... I'll let you know how it goes.