I have the strider plus and love it!
Yes it is big and does have a wide wheel base but it is very stable and still very easy to manovre despite its size.
I have my baby in the reversed top seat and my 15kg two yr old in the bottom seat and they are both happy. With the extension parts on the top seat there is still loads of head room for DS2 and the basket is massive so leg room is not and issue either. He does quite often still fall asleep so the ability to lay him back is a great plus.
And I dont have to take him out if I take DD out of the top because it is so stable.

We were looking at the P&T Vibe but it was the reversible seat that sold me on the Strider and it is more roomier too.

Good luck in your search and happy to answer any questions about the Strider