never heard of them.
try one of the big boys NetSol, etc.
NW is ok, but a sample size of 3 domains is microscopic! Try them on a few hundred domains and you'll probably get some.
Of course, these days if you're serious about acquiring dropping domains you have to pursue ALL available means i.e. Snapnames, NW, Pool, DropCatcher, DropWizard, GoDaddy and more. Even then your chances are microscopic if it's a valuable domain since most of the main players have private systems and connections.
I have picked up a few names with Namewinner, but I find that almost always, if I win, I win with Pool or Snapnames. IMO - Namewinner is good for those names that you would like, but it is not that big of a deal if you don't get it.
I have picked up a TOP domain name with namewinner - However I also ended up paying quite a lot for it :-)
I have aaso a couple of other good domain names with NW. So I am very satisfied.
In my expiriance the better (more expencive) the domain name - the better namewinner gets.
Also - Enom - has the same kind of service but it's a $99 fee a month just to get in there and start bidding. The problem with Enom is that you will always get bid above in the last split second of the auction - I HATE THAT :-)
I bid on 10 domains so far ... some got out of reach pretty quickly (read the $100 ceiling imposed by NameWinner) but I get the minimum bid ones for just $15-20. Such a sweet deal :)
You will need to raise your ceiling. No cost involved. Trick is, search for the domain names deleting in say 3 - 4 days when the first bid is only $15. Most of the time if you are lucky it is still on $15, but can be also up to $30. Then immediate put your limit in (proxy), say $500 for that particular name, done! You only pay your first bid, be it $15 or $30 (incl. registration). Anybody who would like to bid after you will have to bid higher then $500 (AND PAY FOR IT!). Simple.
I have gotten many domains from NameWinner. I would say that if you have the highest bid, there is maybe about 1 out 5 chance that you will get it, but the problem is that good domains always have multiple bidders. Expect to pay on average around $100-$400 for PR5 and $300-$800 for PR6 domains.