Biggest problem we have with it is it won't tighten. We've had it in, and apparently we're doing it 'right' but even DH has a hard time pulling the strap so it tightens. And then the bit at the bottom where the strap you tighten from comes out of has broken 3 times now. We've had the seat replaced twice for it breaking, and the third one has also broken, so we're going on to our fourth soon. SEems a bit strange that we seem to keep getting the same faulty part. Plus the head rest won't stay up. Every time I go to put DS in I have to pull the head rest up again, and even with it at it's highest point the shoulder straps still come out below his shoulders. I have read/seen in many places that for the seat to work at it's optimum the straps are suppose to come out above not below the shoulders. Again I brought it in thinking I was missing something....but nope, I've got them set at their highest setting and yet they still are below his shoulders.