Not too bad.
No really, I ve built a proof of concept with two bluraysleds. It works!
Aligning is a real pain in the ass because of the short FL lenses.
I built a 1:1 telescope one fixed and one actuated lens.
Nice thing is besides focus you can swiffel the lens along two axises.
So you can control the elipsity of the beam too.
The thing is not too fast and you have to stay clear of large amplitudes and the resonance frequency.
Once the coil jumps out of the magnetic field, it is broke, you'll have to replace the sled, and align it all over again.