2 little life ones, one from a car boot sale (full size, all the extra rain covers etc.) and one from a little life rep, the lightweight smaller job.. ex demo stock for a tenner..
Very good, both of ours have paid them the highest possible compliment of a) lasting more than a couple of hours in them comfortably and b) falling asleep fairly readily.
Been up plenty of hills and mountains and conversely are great around the house when the littlest is a bit clingy and mum has stuff to get done.
Worth spending a bit on I think, we tried a couple of cheapies and boot sale bits and they just didn't work as well, plus we'vew had so much use out of them – like you say in many places they're more useful than a pushchair and the kids seem happier in them.