My brother is a welder/machinist by trade and this is info I got from him. I have not personally used the Harbor Freight helmet.
I don't know how familar you are with Harbor Freight, but with most of their stuff it seems like they take a brand name tools and figured out how to make it cheap... in both cost and quality. I don't normally buy stuff from them.
I cannot provide you with tech. data that will back up what I posted. I guess it's more my opinion than anything else at this point.
Personally I like saving money, but I will normally buy a brand name item, since I know it will be of decent quality.
I suppose the Harbor Freight helmet would be fine if your not welding much. If I was in your position, I would just buy a regular helmet, and when you have enough money to get an auto dark, get one. They are nice, but not "needed".
Some of that itch is fumes, but it's also that momentary flash you get. It's not enough for you to really notice, but after a while you will. Some interesting info... .
My Dad and brother work for JM Huber wood mill. They had a safety bullentin come down that people shouldn't weld with contact lenses. The reasoning was that the contacts could "melt" from the UV light and fuse to your eyes. I weld with contacts, never had a problem, but I wonder if I got flashed too much if that could happen? That mill is part of a multi-billion dollar corporation, so it's not like it's some guy at joe jim-bob's weld shop is saying that.
When I got mine, I bought my welder than same day. Got bascially everything I needed for a nice discount since I was spending around $1200.