OK, lets's take the current Ladbrokes deposit SUB as an exmaple. Deposit £100, play it through once, then you're awarded a £100 cashable bonus. In order to cash out, you must wager the bonus 100x (assuming you're playing table games such as BJ) which is a lovely chunk of WR totalling £10,000 (that is of course, assuming the pre bonus one time turnover is included in that 100x WR, otherwise the WR is actually going to be £10,100).
I use the following to calculate the edge;
(Bonus/WR) x 100 - House Edge%.
£100 Bonus/£10,000 WR = 0.01.
0.01 x 100 = 1%
1% - 0.45% (House Edge) = 0.55%
Our edge is therefore 0.55%, which means over 10,000 of wagering our EV will be £55.
0.55% is pretty tight. So my question is, who would accept that and who wouldn't? It will be interesting to find out people's opinions on this. I wonder if some will say they would forefit the bonus and rather opt for the various promotions that laddy's periodically come out with.