One of the most important aspects about this software is flow, ESPECIALLY when it comes to how your customer buys from your site. I find that OSE Membership has the best flow of all the membership components out there, it's just plain simple for the customer to buy a membership using the software.
Configuration is very easy as well. I was able to do it without the documentation but if you need it it is FULLY documented leaving no questions as to what you need to do.
And don't get me started on support. I had 2 glitches that I could not quite get a handle on, and the OSE Membership folks took care of me RIGHT away and solved my problems.
I am now on my way to earning money with my membership site!