Best wishes for finding the perfect guy!
In my area (and my age group), the people on Match.com were almost identical to those on POF, on SeniorPeopleMeet, on OurTime, etc. The only one that was not a carbon copy of all the others (as far as membership) was OKC. That's why I ultimately put up a full profile there.
Personally, I think it's worth putting up a free profile on as many sites as possible, to give yourself a chance to browse the largest number of different people. Then, if one site stands out over the others as far as having more of the kind of people you think you'd be compatible with, then throw your money that one site for awhile.
I also know at least one person per site who has met the love of their life through the site. Even know some who met through eHarmony and ChristianMingle (two sites that I, personally, wouldn't use).