I LOVE ours. DS1 is nearly 4 and DS2 is 3 months old. We have a bugaboo bee though. The board has been designed so it sits to one side, it folds up perfectly with the pram and pivots up when not being used. I use it everyday and its actually easier now with 2 kids than 1 as DS1 loves sitting on it rather than being bribed/yelled at to go to daycare!
If I didn't have it I'd put the baby in a carrier and put DS1 in the pram. He hates walking, grr.
I'd go to the shop and try it out, sounds like the main issue is if it gets in the way of walking.