On my Stumps Prince, I easily had 10-30 degrees variation from side to side in the cook chamber. The bottom shelf, especially where the heat came out from under the heat baffle, was all but unusuable in my Prince. The SS-2 has a diffuser that disperses the heat much more evenly across the racks. I have seen more than one Stumps user talk about rotating their food from top to bottom and side to side to offset some of these variations. In my SS-2, guess what I rotate..nothing. I have filled them both with Polders, and biscuits, the SS-2 has less variation, your mileage may vary.
As far as moving it, my SS-2 rocks back like a dolly, and I just tote it around. The Stumps had 4 hard surface casters, to get it in my garage over a 2 inch gap between the driveway and garage, it was a load. I had to lift one corner up, then another, and then pull the whole thing in..SS-2, I lean it back, and pull it in. I believe you can now purchase all terrain tires for the Prince and or a dolly system, for an additional fee. The off road tires were not available when I purchased the Prince.
As for easier to clean, all of the grease in a Stumps goes right to the floor of the cooker, and is channeled into a drip pan. The majority of the grease in turn bakes onto the cooker floor. Its not a big deal, but I like my stuff clean. If you would like, you can aluminum foil the heat baffle and floor of your Stumps. The grease that doesnt bake in is transferred to a pan under the cooker which then need cleaning. In the SS-2 I put a sheet of foil in the grease catcher/diverter, the grease then goes through a hole and into a catch can which I toss out after the cook. No grease pan to clean, much less foiling to do. Zero grease on the floor of the cooker, equals much smaller chance of a grease fire in your cooker.
I have no problems with Stump's,it got us a GC on its maiden cook. I can't honestly say as fast as I go through cookers, I may not have another one.
However, someone asked for an opinion, and I think the SS-2 has some noticeable upgrades.
Matt