I'm going to be the lone voice of dissent, I'm afraid, as my toddler could escape from his.
I think we had the Infinity Pro, it was great in all the ways others mention, easy to fit, move between cars etc. But, my then-17mo managed to escape from it three times in one week (twice in one day, the second time he actually ended up standing up in the back
).
I emailed Kiddy, who said that they recommend that someone sits in the back with the child to ensure they don't push the cushion off. Err, not really practical. So I sent it back and they refunded me.
There are a few reports of this if you look at the Which? reviews.
I was convinced of it's worth in a crash, but if your child can escape from it then it's not much use, is it?
I now have an extended rear facing seat with a five-point harness and a Five Point Plus to stop him from escaping from that (I have a little Houdini!).