Mine is an older gel-coated Kevlar model that I bought used. It weighs an honest 37 lbs. The boat is extremely fast when paddled with a double bladed paddle and can keep up with most other boats out there. You can also paddle it with a single bladed paddle, but I'd recommend a shorther shaft due to the low seating position.
Initial stability is good, but beginners might find it 'tippy', a characteristic common in Bell boats. Secondary stability however is excellent. The guy I bought it from said I'd probably fall out before tipping it over and I think he's right. Leaning the boat helps in turning. The open cockpit allows you to move your legs around somewhat and reduces fatigue, at least for me.
For big river or Boundary Water type trips I think the Rob Roy is hard to beat. Carefully packed with lightweight gear you could do a week long trip in it. An ideal load would be 300 lbs, but Bell claims you can carry 550, although I don't know where you'd put everything. I wouldn't recommend it for twisty or rocky rivers or in whitewater as it doesn't turn quickly and punches through waves rather than riding over them. I'd also recommend a spray skirt in choppy water. All in all I love the boat. As Bell advertises it lends a kayak's speed to a canoe's ability to carry a load.