We have the strider plus and it's great. What kind of car do you have? We have a wrx and the plus fits in there. I do have to remove the main seat and put the frame/bottom seat in first and then put main seat on top which is no biggy really.

I find the strider really stable. I can leave DD on the bottom seat with the top seat empty and it won't tip. Don't know how it will go when she gets bigger though. However by then she will probably move to the main seat as DS won't want to be in the pram. Or if we have a third I'm thinking of getting the capsule for it and she will stay in the bottom seat so I guess it's designed to hold a toddler. I believe both seat limits are 15kg each (could be more not entirely sure).

The seats are easily removable and I also like how DD can still look up and see me. The strider plus was also cheaper than the P&T.