I bought a TCII, 61" deck, Kohler 29HP EFI last spring and mowed 4 acres of sort of bumpy to lunar landscape bumpy lawn at least once a week all summer. My only concern with the TCII is that the frame might fatigue over the long haul with the weight of the 61" deck coupled with the jarring it gets from our ground. If I had $4000 more in the budget, I'd have bought the TTII just for the frame but my mower was already several thousand over what my wife had alloted, so I'm thankful to have gotten what I did and remain married. All that said, it's a wonderful mower. It has all sorts of power, and the cut, even in the awful areas of the yard, is great. It's comfortable too; the suspension seat is awsome and makes mowing bearable even in the roughest areas.
I guess what I'm suggesting in way too many words is buy as much as you can within your budget and don't look back. Good luck.