I have a Weber 18.5" one touch gold. I cook for 7-8 on it, although I have lots of grilling experience. I char-grill chix pieces, chops, pork or beef steaks, wings, anything smaller. I have used it for indirect cooking of pork loin (a halved whole loin, 9lb give or take, 2 pieces side-by-side) and it did a fantastic job for that...superb fire control. The unit is so air tight that I use it to kill my left-over briquettes from my smokers...just close the intake and top vent, pop the lid on and walk away...fire's dead in about 3-4 minutes and the grill is cooling down shortly after. BTW, the bowl, grates and lid are heavy enough to retain some heat for less temp swings during adverse conditions, as well.
If you will cook for more than six regularly, I would suggest going with the 22.5" as it is 50% larger (360sq in grate area vs 240 with the 18.5").
I highly recommend spending the extra coin for the
Weber kettle. They're built to last and designed to perform like
every charcoal grill should. I can do things with my Weber that I wouldn't even consider doing with the cheapos I own, now that I know how easy cooking on the Weber really is. Very few brands can achieve the performance of a Weber without serious mods (been there, tried that), and then you still have longevity issues to deal with (corrosion, etc).
Eric