I got an orion lathe for $450. it does its job well but does seem to allow the arm to vibrate a bit while workin. I sharpen the carbide bit at work on a grinder (very fine) and get approx 10 arms before it starts to lose performance...

If I were to buy a new lathe, I wouldn't be fused about a diamond blade but I would want bearing guides to eliminate the vibration, and a dual belt...

Thats my exp.. hope it helps...