Although I didn't end up choosing it as my go-to tent, my limited experience with a TarpTent Rainbow did not, in any way, give me the impression that it was flimsy. It was well-constructed, and the fabrics seemed as durable as those in any other lightweight tent, including the Carbon Reflex I came to prefer.

The only concern I'd have about the Rainbow is one that I also have about the CR1: since there is only one arched pole supporting the structure, with stakes providing the rest of the support, I'm not sure how stable the tent would be in high winds (as opposed to a plain-vanilla dome tent, with 2 poles crossing at the high point.) And I'll readily admit that this is a concern only because I've never had any experience with a single pole tent in high winds. Properly guyed out, from the additional tie-out points on the Rainbow and CR1, they may very well both ride out a 30 or 40 mile an hour wind; I just don't have any way of knowing. (I'm not going to seek out such winds merely to satisfy my curiosity, either!)