I am thinking about paying for P411 or date-check. Date-check shows all who are advertising, just shielding certain information only available to members. Almost all of the "hidden' information is available on TER to basic members. I therefore am not so keen on date-check.

 P411 shows only those who wish to be seen by non-members.  For Maryland, P411 reveals 41 of 113 ads. Of those 72 ads only available to members, how many are active providers that I may be interested in meeting? Are there a trove of UTR providers there that do not advertise elsewhere?

For example. London Shaw used to work for DCMD, then she went indy. Her most recent reviews are from November meetings. For the last 2 months, if you searched her name on P411, a members only listing returned. (now it says that there are no active providers with that name.)  I assume she has retired, or at least not seeing new clients. Who are these 71 members only providers? Are they worth $129/yr to have access to?

P411 uses and displays profiles.

I would say over 95% of providers listed on P411 are also members of TER. In rare cases you might find a provider or two with a profile on P411 but not TER. In your case of Maryland, those other 71 providers are probably already members of TER. All they have done is request that their profiles on P411 be viewed only by paying members and in some cases only members with references or okays. Access to basic only members is disabled.

If your primary reason in joining P411 is to find UTR providers, you are wasting your money.

GaviaImmer is correct.  But if you are joining P411 to help with screening it is very worthwhile.  Since joining P411, when I introduce myself to a new provider I give her my P411 id info as well as my TER handle. So she can see how many P411 oks I have as well as view my TER White List and read some of my reviews.  I've never been asked for more screening info than that since joining P411 and offering this info on my first email contact.  In fact, I've had several girls thank me for offering the info right up front and making their job easier.