FJ - i have a p&t and basically bought for compactability.
HOwever i think the side by sides will definately entertain for longer BOTH children as they will be able to see what is going on!

I am not sure how 2 toddlers int he P&T will go, so i think you have made a good choice to try the other type

Perhaps just hang onto the old pram until bub is a toddler and see how each fair out?