Tenney is definitely not SoNH. Ragged/Dartmouth maybe but I think of them more as central NH. Ragged could likely be considered central NH as well. I consider most of the Lakes Region central NH except the southern part of Lake Winni.
Any ways, let’s talk “south of the White Mountains”. Tenney wins for tame old school meandering groomers but is not great for anyone with a pulse. Whaleback wins for best small area with amazing terrain, Dartmouth wins for best overall on a mid-week powder day. Gunstock wins for the views. Pat’s wins for night skiing. Ragged wins for the glades (unless Whaleback has a lot of snow and their glades are open). Crotched wins for high speed groomer laps. Sunapee wins if you want to waste your money for expensive over crowded icy groomers. I haven’t skied Granite Gorge or McIntryre but they seem like local feeder areas.
Personally, I’d put the top three for South of the Whites in NH as Whaleback, Dartmouth, and Ragged. If I wanted to lap high speed groomers (I don’t), I would give the nod to Crotched.