I don't know how I ever did without an auto-darkening helmet before.
This helmet is fast responding, and works very well with arc, tig and mig welding. There is a 'grinding' mode, so that it can be used without te darkening shade activating. For gas welding I found that it didn't activate (just some moments when the flame was too high). As the glass is tinted, I believe this is no problem, and after some time welding, my eyes seemed perfectly fine.
You can adjust the tint level, and the reaction speed, so as you get a feel for the welding you're doing, you can fine tune the settings. It is fairly light weight, and the head-strap is adjustable, although I found I needed to make this fairly tight for the helmet not to push down over my brow.
Overall very pleased. As it comes with spare glass, and a spare headband pad, I think this helmet should last me a long time, so long as the electronics hold out.