Hi. Debating on what double pushchair to get, HELP?

I have a son already and am pregnant with baby number two. My son will be 2 in Dec. and the baby is due end of feb, so he will be 26months. Now i am aware that i will need a double pushchair, although my son walks well and runs around too, he can't be expected to walk all the time at that age. I have ruled out the boards that attach to the pushchair and am now choosing between a side by side double pushchair or one that is in front of the other one.....I really can't decide on which one....Pro's for the side by side is that i feel my son might prefer it so he can see his little brother or sister, but Con's, not practical in the shop.......Pro's for the ones in front, easier in shops, but not sure the baby gets a great view. Now you may say they won't know but my son was such a nosey baby and after about four months was pulling himself forwards and sitting up in his pushchair, whilst holding on of course...also concerned my son will keep wanting to turn round and look at the baby etc..........What to do, i haven't got a clue?...all advice on both welcome. PLEASE.