I have two babies and have had 5 prams! It takes a bit to get it right and I made a couple of mistakes Now I've got it pretty right though.

I bought the P&Ts and hated it and DD2 really hated it too. TBH I would get yourself a single stroller now and then a double side by side when your next bub comes along. DD1 is nearly 21 months and is still very much in need of having her own pram seat, as opposed to just a toddler seat. I have a steelcraft duo and its great for both the girls - cost $240, folds up nice and small, light weight, decent storage.

I have kept the P&Ts but don't use it at all for both the kids. It is dragged out on the rare occasion I am out with just one of the girls and I'll use it in single mode for DD2 in another year or so when DD1 is able to walk for the whole of a shopping trip.