I've tried a bunch.
My favorite hood shell is still the old Vulcanized Huntsman. It will last 20 years, You can drop it off a 10 story building and just climb down and pick the thing back up. It's not super light, but it will also never crack or melt.
I don't care about flames, or jokers, or teeth painted on hoods.. (my students love this stuff)
My few favorite design for auto dark is Optrel. Medium light, comfortable, nice view, My cheaters fit, replacement covers aren't too spendy, and it vents good. I don't favor the super light hoods because they don't last long with alot of overhead SMAW or FCAW.
But really, any of the other major vendors, Speedglass, Miller has a few, they are all safe and flexable.
If your going to weld high amps or aluminum than it's best to look for an auto dark with a range of shades.
Lawrence & Denny both had good options. It's really how much money you want to spend. The Huntsman helmet is relatively inexpensive & virtually indestructible. It can be had for less than $30, then just pop a lens of your choice in. I have used Huntsman Auto View lenses for over 10 years & like them a lot. They make several different models & price ranges. They are on the upper end pricewise, but I like them. Miller makes a less expensive helmet/lens combo with many features for under $200 I believe. I myself prefer Fibre Metal helmets, they are around $40 give or take. The ones Denny eluded to from Harbor Freight are a good, cheap helmet for someone without the funds to purchase a high dollar automatic helmet & they work well for the money.
I bought an 'i Vue' brand cheapie lens for my spare helmet awhile back. I thought it was junk. It wouldn't TIG all that well, it shut off a lot, even after messing with the batteries & stuff. Just my experience with it.
One thing too, to keep in mind is how you like the orientation of the window. (These would be the big window helmets) The Huntsman helmets use a vertical window, the Fibre Metal brands, a horizontal one. Automatic lenses are made for both. Like Lawrence, I prefer plain helmets without flames & stuff. I like to put my own stickers on :-)
One other thing I will mention, at least of importance for me, is that some of the high end helmets such as the Miller & Speed Glas use special curved & contoured cover plates to protect the lens. The only thing I do not like about these, is if you were on the road welding & your cover plate got a load of hot slag dropped on it, you had no extras & you had no LWS nearby to purchase a replacement last minute.... You're screwed!
The Huntsman & Fibre Metal helmets use a universal rectangular FLAT cover plate available nearly ANYWHERE that sells welding products, such as a hardware, Wal Mart, TSC, whatever. Anyone can forget an extra cover plate, I sure have before.
Just a few things to consider. You may want to purchase a better helmet in the future, you'll have a little knowledge going in anyways. After you do some research, ebay is a good place to pick up a helmet, as long as you know what you're looking for.
Good luck S.W.
EDIT: I thought the "Miller Killer" sticker was a nice touch, especially since I use a Blue machine :-)