partypooper,

They are unitab prices. So best tote might add 5% overall and betfair could add up to 10% more which is almost breakeven.

One place which I have ear marked for research (which someone else may be able to rpovide me the stats for) is the gain by using betfair for place bets. I believe place betting on betfair can be very profitable but I am yet to prove it.

The reason I think this is because it isn't rounded down to the nearest 10c. Also you can get fixed odds which can be a great assisteance for certain selection methods.

Good Luck.