I've put a Miller Digital Infinity, Lincoln 3350 and Optrel Crystal 2.0 next to one another and the Optrel has the clearest lens, no doubt about it. The headgear on the Optrel was recently redesigned and that addresses the majority of complaints (aside from price) I've seen about the Optrel. The only other real criticism has been that generic cheater inserts won't work.
I have yet to see anybody claim they were unimpressed with the clarity of the Optrel lens, or how the electronics worked on them.
I don't own an Optrel right now, because I have literally half a dozen shields, but I will eventually buy one. Two of my coworkers bought them after I raved about the clarity, and both guys love them as well.