I have the Rainshadow and have packed with it in the West Canada Lakes wilderness in the Adirondacks. The terrain there is very overgrown, even in established campsites. I pitched the shelter in some tight spots, without too much trouble. The footprint isn't really that much bigger than a two person tarp (which has guylines stretching out beyond the edges of the tarp).
The Rainshadow is huge--a true three-man shelter. I've never had 3 adults in the shelter, but I had me (5'11, 160), my 12 yr-old son (maybe 85 lbs) and a 6'4 giant (going probably 260 lbs) and the shelter was so spacious we couldn't find each other.
My minor gripes with the shelter:
--the entire body of the tent is all one piece, so even if three are sharing the tent, it's weight can't be shared (other than by alternating days carrying the shelter); one person can carry the poles, one person can carry the rest of the shelter.
--b/c of the all one piece design, it's bulky; three people sharing that tent are thinking ultra light, low volume packs, but the body of the tent is a pretty large package for a smaller volume pack;
--it can't be folded into different shapes without removing the cross bar. This isn't terribly hard to do, but it does add complexity to the set up and take down that is not otherwise apparent (if you want/need to pack it a different shape);
--very slippery inside; I think this can be fixed by painting silicone grip lines on the floor, but that's always been an unattractive solution for me.
All-in-all, these gripes are minor if the shelter otherwise fits your kit, so to speak. But for me, I rarely use the shelter, unless I'm sharing gear with someone who is not an ultralite hiker or if I am traveling in a group of 3 and expect a lot of bugs.