All of the helmets you listed are very highly regarded, so it will come down to a matter of personal prefrence. My prefrence is the Marrow_Sun, which is a fiberglass version of the Mystery Helmet. This helmet is widely believed to have a direct relation to one of the original helmets, and in my opinion, is the most accurately shaped. The rest of the helmets are all original sculpts by their respective artists. Some people with larger heads prefer the MLC helmets because of their size. The MSH and MSH2 are both extremely impressive, though hard to come by as there were few made. The BobaMaker helmet looks impressive as well, though I have not seen one painted up yet. Basically, I don't think you can go wrong with any of those helmets, just depends on what you need or want.
Also, beware of the recasted "Mystery" helmets on ebay. From what I have seen of those, they are made with inferior quality materials, and sometimes cost more than a real Mystery helmet from one of our members here. My suggestion would be to buy from a member of this board.
