i'm using a $30 chinese one off ebay, it has both darkness and sensitivity adjustments on the outside (which is nice). It's a bit finicky on the sensitivity adj, i had sometimes issues with it flickering (and that's no good since you can't see afterwards) and i don't know if it's b/c it's solar powered or b/c it's crappy (or maybe both) - i got it adjusted once and it worked and i didn't touch the sensitivity ever since (been working knock on wood so i don't play with that button anymore). If you weld a lot i'd say go for a name brand, otherwise one of these would do the job ok but not for a pro welder for sure.