The auto darkening lenses make it really easy to tack exactly where you want it, and the nice ones adjust for shade, delay, and sensitivity. The more you spend on the helmet itself,....the more features they have too.
I currently have a couple of fixed shade Jackson helmets with the big window, and an Optrel adjustable, which goes from 5 to 13. I do TIG on thin stainless, so I use a low shade for that work, and use a 10 at higher amp settings. When stick welding, either the fixed shade or the adjustable works fine, but I'm really hooked on the adjustable. I will make a small change in shade when changing from 1/8" to 3/32" electrodes.
FWIW, I've worked around welding for 38 years,.... you only have one set of eyes. Spend as much as you can afford.
KCBS - CBJ
Big Green Eggs, Big Drum Smokers, Big Chiefs, Weber Smokey Joe "Custom Tall Boy"
Oil Patch Horizontal
Visit my Cookin' Site by clicking HERE
Barbecue is not rocket surgery