RS2000 is mainly in the mid West, so if you're not from there I'd go with one of the other two. I belong to both. I started with P411 because they had an 800# to call and work out what verification info I needed to provide. I don't have a work # (which most providers want, too) so we worked out some different personal info I provided. It's also nice the P411 is based in Canada so they are safe from US LE. D-C is good, too, and each have very similar features: PMing providers, lists of favorites, many gals who discount for members, etc. I like the D-C feature that displays on a calendar the names of any of your favorites that are in a specific geographical area. Good luck!
PS: I don't know if D-C has added an 800# by now or not, so check.