Other sites

Hello everyone...sorry I been out of the loop and I'm a newbie here. I tried the search part and I could not find any thing on my subject.
My question is...I have look at the other site that ECCIE sponsors'.
xmatch, aff and rudefinder. Are these good sites and if so which one would you preferred.
Thanks
TBW

Hoping I did not post this in the wrong section.......Anyone willing too help?

This is an ad I think

Okay Cool. Has anyone had any experience with them though?