"Progressive" weight of the quads I've owned:
2002 Honda Rancher 350 electric shift (solid axle, carb, air cooled 5 speed "nimble, adequate power, rode rough, hard seat") = 535# dry weight
2004 Arctic Cat 400 (IRS, belt drive, carb, air cooled, "big frame, tall and underpowered, but plush ride") = 649# dry weight
2002 Honda Rubicon 500 (solid axle, carb, air cooled, auto "adequate power, rough ride") = 600# dry weight
2008 Honda Rancher 420 electric shift (solid axle, fuel injected, water cooled 5-speed, "adequate power, rode rough, loved the fuel injection for cold starting and high elevation use without re-jetting") = 586# dry weight
2013 Yamaha Grizzly 550 (IRS, belt with auto clutch drive, fuel injected, power steering, heated grips, soft seat, lots of ground clearance, "relatively small overall size, really like everything about the machine short of gas mileage is much lower than a gear drive Honda due to running at higher RPMs all the time with the auto belt transmission). = 648# dry weight.
Conclusion: If I were buying a new quad today, and I am not, I'd look hard at a Honda Rubicon 520 with the foot shift 5-speed transmission, power steering, IRS etc. Rode one a little bit while caribou hunting in Nunavut a few years ago. Had a great ride, soft seat, but still offered the low engine speed, great gas mileage and "putting around ability" of the 5-speed manual shift......way nicer than the old the Honda 450 Foreman solid axle that was my primary ride up there on the caribou hunt.