So, I don't have the loupes yet (they should arrive this week) but I have ordered a set from Lumadent. I'll follow up at some point once I work with them some.
Why did I choose them? I spent a good amount of time trying on loupes at various lunch and learns and later at our loupes fair and wasn't even interested in Lumadent at first. I tried on several pairs of Q-optics loupes, Surgitel and Designs for Vision loupes. I tried on the Lumadent loupes on just to keep my options open and then found myself coming back to the table over and over again. I just found them very clear and was comfortable with the magnification. They also had a frame I liked and were willing to work with my normal glasses Rx (others will do this as well but you may have a more limited choice of frames). I got a set of 3.3x loupes with a prescription insert and the warm light with the short cord for a little over $1300, so the price was really good too. True, I haven't used them yet, so maybe I will hate them, I don't know, but I feel really good about my choice right now and I haven't broken the bank.
Loupe choosing advice: One thing that really helped my decision was paying attention to color as well as finding a magnification that I was comfortable with. Have a piece of paper with lines on it- my student ID has a bar code, but I hear graph paper works- and look for color bleeding around the lines. You will see blue and yellow bleed around black lines. I think they all do this a little, but I eliminated one brand immediately once I started looking at this because it was so much worse than the others. I hadn't been comfortable with them and it really helped me put my finger on the issue.
Anyway, good luck, I'll let you know how I feel about my purchase.