I've been riding an Xtracycle in traffic for seven years now, and THEY RULE. There will be some tight spots and nimble maneuvers that you will learn to avoid, but in general the handling is quite similar to the bike you're on now. The advantage is that the larger bike attracts much more attention from the drivers, and they tend to give it much more room. This will not be true for all drivers, but most seem to have more respect for the X than they do for a "regular" bike. The longer wheelbase also adds stability in panic situations, and all the extra structure can actually protect you in case of a rear end collision. It doesn't make you invulnerable, but I have been hit from behind by a pickup truck which immediately propelled me and the bike forward ten feet, but did no damage to either of us (me & the bike, that is - the truck took off, so I have no idea how it fared). As for the weight, it will depend on your setup; I think you can get away with 15 lbs over the weight of your current bike for a fully equipped X. It's definitely noticeable, but not too bad on most stairs. There is a nice grip point above and behind the bottom bracket that allows you to carry the bike nicely balanced under one arm. As long as the stairs don't have any sharp turns, it's not hard at all.