I have used the Tria. Your experience may vary, but I found that it was moderately painful on the body, very painful on the jaw (I had to resort to a topical numbing cream), and didn't reduce my hair level noticeably in any location. I have the ideal skin/hair type (fair caucasian with brown-black hair).
If you decide to try the Tria, do be aware that using it on the face is strongly discouraged because if you are not very careful of the angles, the beam can cause permanent eye damage. Plus, the beam will diffuse and go sideways a short distance through your skin, so getting too close to the eye can also cause damage even if the beam is not pointed toward the eye.

Please be careful.
I'm done with home hair removal treatments other than shaving and the occasional epilating cream; I'm saving my money to have a pro do the job.