Hi mate,
your question is very interesting but maybe a bit more complex than you realize I think, but I'll do my best to explain what you need to consider.
@VorpalF2F: not wrong but I'm not sure that's a very helpful approach to look at it if you want to transfer the results.
I try to be a bit more comprehensive while sticking to actual numbers:
First of all you have to account for the lower Rake at PokerStars as well - less Rakeback does not necessarily mean less money in your pocket, if, like at PokerStars, the Rake is lower as well in return.
Let's do a very simple example with fictional numbers, you should easily be able to transfer that to your actual results.
For a start, let's assume you don't pay any rake. For a NL100 game it could be realistic that you win 10bb/100 from your opponents (if you're quite skilled obviously, I chose this number for ease of calculations).
Now when rake come into play you will find that a realistic value how much you pay on those stakes in a fullring game is 5bb/100 in the iPoker network where you have standard 5% rake with $3 cap. For PokerStars in the same game it would be 4,5bb/100. These numbers are the true story by the way, we have simulated that over half a million real hands sample size with the respective rake structures.
So you effectively win 5bb @iPoker and 5,5bb @ stars over 100 hands. That's the winrate your tracking program shows.
Now Rakeback comes into play. Let's say you get 50% on stars and 80% on iPoker, i.e. you effictively pay only 50% of rake at stars and mere 20% of rake at iPoker.
That changes your effective rake obviously. Now you effectively pay (5bb*0,2)=1bb/100 @iPoker and (4,5bb*0,5)=2,25bb/100 @stars. Obviously in this case your significantly better off with that iPoker deal, leaving you 9bb/100 instead of 7,75bb/100. This however shifts with the stakes played, as effective rake differs.
Now obviously there's still many unknown variables in this whole calculation. First of all there's a different player pool which you might win more or less against. Then you have to consider, that you might be able to play more tables or hands per hour in one room than you you can at the other, or maybe you just like the gameflow better at one site.
You should also consider your cashflow: If you don't pay an amount of rake in the first place, it stays in your bankroll and you don't have to wait until the end of the week or month or until you have claimed your bonus to have it available to play, which might enable you to move up stakes quicker. On the other hand it can be quite motivating to play towards a kind of "paycheck" which you get in a certain interval and a high rakeback bottom line can take away a bit of variance, which is important especially for people who play for a living and need their steady income.
So at the end of the day it very much depends on quite a lot of factors, what is the best option for somebody. It's important to look at your $$-bottom line, but you should also consider other aspects like whether it's hobby or profession, how important a good software is for you, traffic of course... you can add to that list endlessly!
I've written you a ticket incase you'd like to go deeper into these topics, would be nice to hear back from you!
Kind regards,
Hergen