We have just bought the P&T Dash, mainly because they're so readily available. Because my DD is not a huge fan of being in the stroller, I didn't want a side-by-side double because in all honesty I don't think she's going to be in a stroller for a whole lot longer, so I wanted the detachable toddler seat.
So far, with just DD in the P&T I am enjoying it - it maneuvers well, although I haven't done any off-roading. I don't forsee any problems there, though.
We are obviously yet to try it with two kids. But out of the very few we were able to look at physically (not just pictures on the net), we liked it the best.