Not knowing what your definition of "large groups" is, I'll offer this; If I was in the market for a larger capacity cooker and was looking for something other than an offset like a Klose or Gator pits, I would look at a Backwoods(Party or Fat Boy model), Stumps(GF222CM or GF223 models), an FE100(pellets; need electrical to work), or a Spicewine(Medium or Large model).
Have heard nothing but good things about these cookers, they are all insulated cookers and hold temps well, and the Backwoods and Stumps are as close to "set it and forget it" fire control of the WSM as any on the market. The FE100 is an auger driven wood pellet cooker.
There are other cookers out there that people will swear by that are good cookers. Keep in mind that nothing beats some good research. If you can go to a comp and you will see every cooker there that I have mentioned and look at them and then make your decision. All of these have their own web sites, do some googling and you should come up with them. Good luck!