Betfair is a really poor example for odds. They can afford to offer higher odds because the commission comes on the otherside of the wager. If you win, 3-5% commission goes to betfair, adjusting your odds, of sorts.
You are right guys, I forgot about 5% commission on betfair because I never had account with them. And you are right highest payout rate is most important here.
For example the odd I am betting my real money today on Flyers underdog is 1.98 while 5dimes only gives 1.95
Betfair odd is 2.02
Ottawa Senators are offered 1.91 on 5dimes
Real odd I placed money in my bookie: 2.05
Betfair odd 2.1
So every day it is like 0.1-0.2 worse and less profit, in a long run it can make a difference?