K.M.
My daughter had one of these and it worked beautifully. I asked her what advice she would give and she said 'just be careful when food gets trapped in there'. We bought her an inexpensive water-pik and it helped a lot.
She adjusted well to it- no pain, no swelling, not hard to get used to. We are very pleased with the results. I'll admit, I was concerned just like you when we had the discussion with the ortho. It was much easier than we expected!
Good luck to your daughter. Her wonderful smile will make all of this worth it!