Mine has been 'perfect' (no, really!) when we were living in the city, in a flat. It fit through every doorway, got into every lift... and the seating options are fabulous. My two love facing each other :) and there aren't many buggies that would allow you to do that. The shopping basket has carried a LOT of stuff for us and that's real bonus when you have two kids.
I would still be madly in love with it, if we didn't move to a VERY hilly area with tilted sidewalks. I recently had an operation on my left wrist, and find it really difficult with two heavy children in it, on a tilted sidewalk going up/down a steep hill - the buggy kind of 'veers' to a side. So in conditions like that, you need to 'hold' it instead of just pushing it. (Don't get me wrong, it's a lovely maneuverable buggy and my husband hardly has a problem with it) So, if you live in an area like ours and have weak/compromised wrists, I wouldn't recommend it long term (when the LOs get older/heavier).
However, if most your walks will be on level sidewalks on flat land, it's a fab option. So much better than a P&T, where one of th children always gets the 'short stick' and you can't see either of them... It can, by all means, handle the occassional off-road trip, but just bear in mind that if you have close to 30kg of kids/luggage on it, it can get a big difficult.