We have this, used the carrycot and pushchair but didn’t get the car seat. (For a car seat we went with cybex).
I really like the versatrax. I will mention that I bought it second hand. Initially we had a cosatto from my brother because it was hardly used but I hated it. DS hated the car seat. I hated how big the cosatto was - which is most travel systems. I lasted 5 months with the cosatto - DS did sleep in the carrycot of that really well though. Then we moved onto the seat and I knew I needed to change the pushchair.
I manage to fit the versatrax in my Renault Clio. At a very tight squeeze and without the parcel shelf on it fit in the boot. My baby is now 6 months old and we use the seat now. What I really like is it collapses in one without having to take the seat unit off. Now it’s still big but it’s more compact than when the carrycot was in too.
Im now on my second child using it. It’s still in good condition. The basket underneath is huge but most travel systems are like this too.
I have no regrets. We didn’t use the carrycot with my first but we have this time and DD slept really well in it when we were out and about. Can’t say about winter or warmth for a newborn because I had two spring babies, by the winter they have been 6+ months and I got a warm winter footmuff for them.
It pushes fairly well off road. Not extreme off road but I walked around a very gravely rocky path and it managed with some shaking. DS was never a huge fan of pushchairs though, he just loved being carried so half the time I ended up pushing an empty pushchair whilst baby carrying him. This time DD has accepted the pushchair a bit more and I have been putting her in it more due to needing to help my toddler whilst out so we have got more use out of it.
Oh and another positive, a buggy board attaches really well to it without the extenders. It can clip up onto the handlebar too. So that’s what we do with our toddler on occassion now. Other times he just walks or we end up baby carrying the baby and he gets into the pushchair.