I went from a 13in Air to a 15in pro for about a week and a half before returning it, but the size/weight wasn't an issue.
In a bag, the weight isn't noticeable. Holding the machine, it's definitely not as easy to toss around as an Air, but it's not bad. The only time I really felt the weight was when grabbing it with one hand - it feels so dense, I was sometimes afraid I would drop it. That's where the extra pound comes into play - when you're trying to grip it with one hand to pull out of a bag.
The footprint isn't a big deal either. It's larger than the Air, but not massively so, and the screen was a big step up.