I absolutely LOVE our Diono car seat. We decided to purchase one for our two year old and another for our four year old. They were growing out of their Graco and Britax car seats, so we decided to try Diono after a friend recommended it. It is by far the most sturdy car seat we've owned. It's very heavy, but makes for a safe seat for the little ones. Instillation was a bit of a pain, but otherwise I have no complaints. Both kids seem to like the seats and they aren't as wide as other brands (so the middle seat between them has more room).
I highly recommend this Diono!