Date Check is popular in the midwest.  Depends on where you live.

Date-Check is actually the best service from a national level-- RoomService 2000 (RS2K) is popular in the midwest, Preferred 411 is big in Texas, but Date-Check has a national base of providers and clients.

I'm a member and love it when I get a Date-Check gent. BTW, I'm in Miami.

Some services are more popular in different areas than others.  If you're in an area where a given service is popular, then it's probably worthwhile to invest in it.  For example, I go to Dallas every so often, and my Preferred411 membership is invaluable down there; however, it's not as frequently-used in my home area (DC/Baltimore), though it's getting better.  I had a Date-Check membership a couple of years ago, and it didn't really suit me.

Not knowing where you are (or where you hobby these days), I can't make any specific recommendations.  I'd recommend signing up with at least one service, but without more information, I couldn't say which one would work best for you.

Why pay for something you don't use? Wait until a provider wants the date-check reference, and then pay for a month. If you start finding a lot of ladies requesting it, then pay for a longer period.

Given there business models, I think P411 will be big in a few years. It is free to the ladies, so more and more ladies should be joining it. Once the ladies are accepting it, the guys will follow.