Just bought a front engine Craftsman RLS 3500 42" deck, 20 HP B&S OHV motor, with a 3 bag catcher. Got one heluva deal on it for $980 brand new plus the catcher which was $379. Got 12 mos SAC on the sears card as well.
My dad's had one for 5 years now and it's not given him any trouble at all. If the honda engine would have been available, i would have got that, but the briggs has an oil filter where the honda did not. And briggs is suppose to be a good motor.
Plenty of power; the motor doesnt' even labor while cutting, and it has great suction. The motor is a little noisy though, but the Amsoil ASE seemed to quiet it down a bit.
It takes the same oil filter as the 4.7L tundra motor which is 4" long, or you could use the B&S 2" long filter if you wanted.
OH BTW, my yard is 12000 sq feet and it takes me about 45 minutes to mow it, and i only dump twice. My lawn is very healthy and needs to be mowed every 4 days.