Most of the users here that bet on sports are American. I can say this 99% sure, that the majority betting sports using BTC are. With US, many betting customers are very limited in options and thus eventually found BTC and use it because of the convenience. European bettors have that convenience already with one sportsbook or another. Thus, I would highly suggest you offer a couple things:
1) Better lines. Your pre-game lines are 30 cent juiced which is outrageous.
2) MORE games for live betting. Bitbook offers live betting for every MLB game right now, you guys offer 0. MLB and NFL are the biggest sports for live betting for US players.
3) Make wagers graded quicker AND payouts processed instantly. Bitbook and other sportsbooks pay out right away generally whereas players here seem to complain about the time it takes for the wagers to be graded and such.

Ask all the books, casinobitco.in, bitbook and Nitrogen I have placed wagers with all of them. With bitbook I have wagered over 25 BTC already in their live betting area. I have yet to place a bet with you guys because of the above 3 things. Please fix these and focus on more american sports, because honestly that is your main betting audience here.

Good luck to you regardless of whether you listen to my feedback.