We have the same age gap as you, and I also started out with the Beema Q which I loved.

I was never keen on the P&T's, mainly as DD still will sleep in the pram when we were out, and I didn't like the fact that the seat for the older child couldn't recline, so when the Strider Plus was released I bought that and I love it. Yep, its a bit wider than the beema but still fits through most places that you'll take a pram - def not as wide as a side by side, and the valco single is about the same width I think.

I like the fact that I can have the new baby in the top seat facing me, and DD in the bottom (I don't think they endorse this, but it works!) it means that she can hop in and out when she wants - she'll quite often want to walk when we 1st get to the shops but after a while, still wants to pram ride. Other times, I'll put the baby in the 2nd seat at the bottom and DD in the mainseat, and its not tippy at all - its really stable even if DD gets out - unlike the P&T in toddler mode - if the toddler on top gets out, it gets tippy.

The change bag - i use nappy bag clips and attach it to the front of the pram, at the bottom of the main seat itms. I also have a mummy hook and things attach fine to that without hitting the baby in the head.

It also came with the rain cover, boot cover and sunshade, and the 2nd seat has its own hood.

Good luck!