I have a Prg Prerego Prima Pappa. It's done 3 of my kids plus 2 of BIL's and I'm sure it will survive my fourth child too. It's solid, folds up quite compact if you want to put it away in the cupboard or put it in the boot of the car and go visiting someone that doesn't have a highchair.
It stands up well to a 5 year old hanging off the tray. I wouldn't recommend the 5yo hanging off the tray too often but if it can survive that then it's well worth the $200 odd they cost.

The downside is that there are a few too many nooks and crannies for things to get suck in so it needs a good scrubbing every now and then.