It depends on why you want to do ortho. If your only goal is money, then it's probably best to do something else, but I guess that's always the case. Ortho hasn't lost its luster for me because I enjoy the work much more than I did dentistry. I will be much happier practicing ortho than I would have been practicing general dentistry, regardless of my earnings, but that's just me personally.
Money's obviously important, and I think the nature of ortho has changed in that regard. Urban areas are saturated, while rural areas aren't so much. I think it's more of a necessity to have a satellite practice (or two) these days. I personally intend to go a little more rural than I had originally planned, and that's because I've accepted that things have simply changed. I've heard many times, "Decide where you want to live, and then build your practice and you'll make it work," but there isn't enough incentive for me to swim upstream that hard.
Plus, we're in a serious recession. Things turn around. There's probably a glut of 13-year-old kids out there whose parents are waiting on braces for them. Also, in a recession, dentists need to take whatever they can get, including everything from every specialty. Ortho will be less worth their time when we're out of a recession.