Can you elaborate? I don't play any right now, but I'd like to know the differences in the case that I'd want to play on one of them.
Not going to explain every bit because I know you're clever enough to understand the what I'm trying to say. I'll just post the five facts I like about the site.
1. Active users
You don't have to wait much for a match and their forums is semi-active (as active as DNF right now) as well so you don't have to worry about a complete dead community and a empty site. They're also working on building a war scene there so having tournament and war scene in one site would be almost like old DNF.
2. Caring administrators
The head admins there are as active as any regular user and that's one of the things that I like a lot about the forums. It doesn't even take 12 hours to resolve any question/issue you have in the site and the moderators there are also very responsive. They admins there play YGO themselves so they know exactly what the users would like to see it the next update because they regularly play the game on their server.
My personal experience with them is very great. I asked one of the admins if they could make a mac version of YGOPRO Salv. They weren't planning mac version for it but just because one regular user asked them to do something they are currently working on it. I mean how better could it get...
4. Advanced forums
They are using IPB forum just like DNF but they're quite advanced. Their forums is IPB 4.1.x and they add new skins, features, banners etc frequently so you wouldn't get bored of using the same system.
5. Frequent updates
They update their site a LOT and new cards are also added very soon (12 hours at max after official release) so you wouldn't have to wait 2-3 for the cards to get added to the server like we used to in DN.