I spent alot of time at a local helmet shop when a friend was getting his first helmet. I learned, cost doesnt equal better fit helmet. Each helmet brand has its own shape and fit. Some people just cant stand certain brands due to fit issues. My friend went in with money as no issues, the sales guy knew that and still had him try on every single helmet they had.
The pricey helmets will be better quality but if they dont fit theres no thing you can do about it. From what Ive seen, the more you spend the better features you get. They are all just as safe, look for fit then if you can afford it get the features you need.
As far as braking, I use both brakes every time when I want to stop. Its nuts to use front only when the front is only what 70% of your stopping power? Theres situation when you need one or the other yes. I see alot of sport bike guys never touch the rear brake, they say its not needed. Well when the difference between plowing into a dump truck is a foot, youll want to be familiar with that rear brake. The only way to be good at something and have it kick in as instinct is to do it all the time. If you never use the rear brake that one time you really need it you wont have it locked into memory.
If your scared of locking your rear brake and thats why you dont use it, then you need to learn to use it correctly. People would never use the same excuses for not using 30% of the motors power, but stopping they do?