Lots of good helmets out there, but first consideration should be "fit" an ill fitting quality helmet will probably protect less than "lesser" quality helmet that fits you right. Crash protection aside an uncomfortable helmet with hotspots takes away a lot of the fun of riding.
As far as protection goes, any full face with snell certification will offer about equal protection, the extra money goes towards bells and whistles. Colors, vents, weight, removable linings, breath guards, etc...
Visit dealers and try them on, we don't all have the same head shape.Not all helmets fit every head properly. Some people have Shoei heads others have Arai heads,etc... When you do try them on, once you've found one you like, try keeping it on your head for as long as possible before making a final decision.
I remember buying my first helmet, luckily the salesgirl who was helping me choose, insisted I keep a helmet I liked and thought fit well on my head, after about 10 minutes I started feeling hotspots ( feels like a blister starting to happen ).
The helmet should feel snug ( borderline too tight ) when you put it on. When you grab the helmet and move it from side to side and front to back your skin should move with the padding . As long as there are no hotspots you should be okay, the padding will compress slightly with time eliminating the too tight feeling.
Tie the chinstrap, grab the lower edge of the helmet at the back of your head ( nape of the neck ) and try to roll your helmet up and off your head. If it does roll off then choose another type of helmet or a smaller size.
One other thing I'd like to add is to buy the helmet you try on. Two identical helmets in the same size will fit differently. I bought my first helmet after trying on several at the local dealer and finding the one that fit me best. Two weeks later the wife decided that she wanted the same helmet to ride with me. She had tried my helmet and it fit her well so I hopped on the bike and went back and grabbed her one identical to mine and the fit was totally different. Mine fits perfect, hers has play. Still comfortable and close enough to be safe but there is a difference. Fortunately she has alot more hair than I do and it takes away the play for her and fits her right.