Check this : Usenet Special Offers And Coupons – UsenetReviewz you will find all you need about new and old nzb'sites. There are free ones like nzbplanet.net and vip only like nzbsrus.com, you will find a review about all of them. What you wont find is an invite for members only like nzb.su or dognzb.cr. I'll be glad to get an invite for one of them as a backup if one more of my favorites goes down. Do you know somebody who could send me one?
I have to say that I know a lot of people rave on about nzb.su but having recently got myself an account there its nothing special, there are plenty of other alternatives just as good. Don't know about dognzb.cr, never tried it.