I use these in my RZR based race car and really like them. They fit my ear size fine without any issues. I use a piece of medical tape over them and tape them to my ear for extra security during race conditions. Overall they are definitely worth the money and I would recommend them. I prefer these over the ear cups now that I have them. If off-the-shelf ear buds are never comfortable to you in your previous experience, I would recommend going the custom route. If you haven't have an issue with off-the-shelf buds in the past these should work great.
Audio: Way better than the stock helmet speakers.
Fitment: Not so good on me. The left side hurt so bad I had to take it out. I would recommend getting the custom mold ear pieces.