There is nothing really that difficult in choosing a good online sportsbook. Most, will go with what they have heard about, word of mouth. "If the Jones' use BetUS then so will I."
That in itself if the wrong thing to do. I remember a certain lady cooking a pork joint for me, she always cut the right end off before placing it into the baking tray. "My Grandma always did it" she would say. It probably passed down through many generations before I told her that Sunday afternoon why her Grandma always cut the end off.
"It did not fit the baking tray, Grandma has to cut the pork down so it would fit on the tray". "Oh" she said.
So why do people always go with what they have heard. Why not do some research themselves? It could be laziness or that they just do not have the time to go looking for alternatives, but it is quite a big decision that could mean more or less money in the not too distant future.
For example, certain sportsbooks will offer better prices on different events, even the best US sportsbooks [http://www.qwertycasino.com/Best-US-sportsbooks.htm] will offer better prices on horse racing in the UK as it takes them longer to set the prices. They do not have people on the ground, such as the UK bookmakers may do, and therefore it takes them longer to get certain information.
There is also the factor that is different sporting events. US sportsbooks may be specialists in American sports such as Baseball, Basketball and American Football, but on such events like Royal Ascot and the Grand National, they would need to rely on their UK cousins to provide the information needed to give it's betting players a competitive price and that, particularly on the day of the event takes time, and a lot of it.
Have a look at sportsbooks more in-depth, check their prices, are they more competitive than the sportsbook your friend suggests? Do they include betting bonuses or money back on certain losing bets?
Much to look into but very much worth it in the long and short term!