I have used the Easy Twist 2 in all sorts of places.
We live rurally, so it's done a few trips across lumpy fields (not perfectly suited, but managed and didn't break).
Many trips to London (perfect - quick to fold if you need to, easy to carry one handed when folded, light to carry up stairs on the underground, can fold it and shove under a restaurant table or behind your legs on the tube or hand it in to a cloakroom).
Train travel - small when folded, slim to push up the aisle of train not busy. I can fit it in to a four-seat section sideways and my other kids and I sit on the seats around it if I need to. I've never tried to lift it on to the shelf above heads, but I suspect it would be too heavy for me, but doable for my tall and strong husband.
It is small for packing in the boot of both my small car (takes half a Golf boot). I sometimes put it it the front or back footwell, but that would depend on seat positions and car shape.
It the baby/toddler is sitting up forward facing (most of the time for me now) then the centre of gravity is perfectly central on the frame and I can add quite heavy bags to the handles - I have a family picnic bag that weighs a lot when full but hangs perfectly behind the seat. If the seat is parent facing, then you can get a lot into the basket from the front. If the seat is reclined fully when forward facing, the centre of balance comes way back towards the parent, though my beefy toddler is heavy now! It is more stable reclined from parent-facing. It's never tipped over or anything close though!
The reason I bought it was for the seat position - it can sit apart perfectly upright. Most buggies, particularly ones which use straps to pull to adjust the recline, can't come anywhere near to upright, and I had a baby that liked to sit rather than recline. I had a big bulky Joie travel system that was perfect for sitting upright, but looking for a smaller pram with an upright seat was hard. I tried the Joie Pact (folded small and lovely travel bag) but that was so so flimsy and didn't really sit up straight anyway (strap mechanism). The Cybex is perfect for this - it is a lift handle on the back of the seat that stops at preset points, one of which is very nearly 90°!).