I have a couple of Flip one-size covers that I use, but I usually grab a Thirsties cover before a Flip. My baby is pretty squirmy these days and I find they can be a bit awkward to get on. Because they are one-size you have to fold in the sides before snapping it up...if you do this at all unevenly I find that the cover can gape a bit and if you're not careful and it can leak if you have a really wet diaper. I do like the fact that they are adjustable. I haven't had problems with odour and they are easy to wipe clean.
A bit awkward, but good 
