I've taken my Rainbow out a number of times now and I must say I really like it. Compared to my Squall 2 it feel so much roomier and for the small site camping that you find here in Japan the footprint is just right. Definitely my favorite tent right now. I'll be going higher up (3000 meters) this summer and hope to take the Rainbow along. We'll see how it fares in strong winds.
When I bought the Rainbow in March I initially had concerns about its stabiity in high winds, as Will pointed out, so I asked Henry to sew some loops to either side of the arch, which he cheerfully did (take a look here scroll down and you can see the loops in the photos). So far I haven't had occasion to need the loops, but when fitted with guylines they do help to stabilize the arch laterally (front and back), though the top of the arch still oscillates when I give the tent a shake.
I replaced the included arch pole with a beefier one made from Russian space program aluminum/ scandium alloy available here in Japan. I figure that the extra strength will come in handy.
For the hood on the rear window I immediately didn't like the way it flopped, so, taking a cue from European tunnel tent designs, I sewed a strip of 1/4 inch closed-cell foam into the brim. It's very light, keeps its shape and rolls up well with the stowed package.
Since I dislike velcro with...er... all my bristles (^J^)/" I cut the trekking pole fasteners from the ends of the arch. I might replace them with some bungee cord concoction if I ever feel the need to have the tent free-standing, but staking it down is what I will most likely always do, so right now I feel I don't need the fasteners.
As to the fitting-the-pole-into-the-ends-of-the-pole-sleeve problem, it's something I've been frustrated with all my TarpTents since I first got my Squall. I therefore cut some tiny trapezoidal pieces of wedges from a pet bottle, about an inch long, with the wider end about 1/8" wider than the width of the pole sleeve opening. I shoved the wedge narrow end first into the opening all the way in. Now what I do when inserting my pole is squeeze the wedge at the sides, the pole-sleeve-opening gapes open, and in I shove the pole (this IS PG rated!).
My floating floor doesn't perfectly match the attachment points inside so that often the floor tends to slack a little bit (nothing earth shaking though). I'm still considering adding cut lengths of plastic straw to the corners of the floor (like the bathtub floor corners of the SpinnShelter User Tip from Gossamer Gear) to help the side walls stay up.
With my antagonism toward furry creatures, I'm still not sure how I feel about the velcro on the door, but I'm going to give myself quite a few more times to try it out. I may possibly add a coil zipper if it just doesn't grow on me, but that is a matter of more experience with the tent.
So far condensation hasn't been much of a problem, but I am worried about the sudden drops in temperature and the blowing grit up in the Japan Alps, that has a way of getting through the perimeter netting, so I considering making a propore (if i can find the material!) sheet that I can hang from the ceiling for condensation, lowering over myself when the grit and cold are blowing into the tent, and also using under my hammock when I decide to go with that.
After I get some use of the tent up in the alpine mountains I ought to have photos so I will try to post them at the end of the summer.
Whatever little glitches the Rainbow may have it is a wonderful and versatile tent. My hat off to Henry!