Before all the posturing and put-downs arrive for mentioning POF and "OLD." I'll chime in with a perspective.
It's been a long while since being on POF, but even in a larger city, there were two types of women that opted to be a paying member.
The first set... were women that (at least, judging by their profiles) looked to be a cut above the norm.
The second set.... were the ones that looked like they haven't had a date in 10 years.
There may be a few exceptions to this rule, but it's the exception.
If you are thinking of becoming a paying member, check out the male profiles and see if the above observation holds true for men as well.
Going by memory, what are the advantages? Do you really want your profile to have that "gold star" or what ever they are symbolizing on your profle (alerting everyone that you paid for a site that is for free) ?
I"m guessing that they still have that "wants to meet you" function. Personally, I thought to myself... why would I want to meet some gal that clicked the "meet me" function 50 times to 50 different men in 60 seconds.
The only advantage I could think of is that I read somewhere that you are able to view their sibling status. Because middle children grow up to be more of the "pleaser" type, this could has some advantage. Personally, I don't see this one positive outweighing the negatives.