I 2nd m n' c. I do SR first. I use a unique email for IB$ and only do it if I haven't done it on SR. For some reason, even with the same demographics it is harder for me to get qualified on IB$. More often than not, I have my mom come down (she lives down the street) or ask my friend to try when she comes over for end-of-day-destressification-lifeisdrivingusinsane-coffee.
I wished I had taken better advantage of the IB$ surveys, my balance has really jumped since starting.
I did read somewhere they take a $3 fee out for p/h, so take that into consideration when cashing out. And they work on a net30 (cash out Sept., won't mail until Nov. 1), so it will take about a month and a week or so to get your check (I actually have never cashed out, just from what I've read, may be incorrect but I'm sure someone can clarify).