I'm going to do something dangerous here, but:
ReLite is probably the best
I do not think they are the best. Although the 3 top clans (ReLite, WM and Apex) are very very close together there is one difference. Relite mostly has 1 or 2 players in the top 10. Apex currently has 2, but has 3 more players that might get into it (Relite has 2). Now the problem with WM is that it's members are slowly going inactive or leaving. The ones that stay behind are mostly not participating in the ladder.
I think that although Relite might have beaten WM (I'm guessing you are talking about a clan-league or so), you should judge them on long time period performances. Now i know that Julkorn is currently first on the ladder, and he really is doing great, but Apex has spot number 2 and 3. So which clan is better, the one that holds number 1, or the one that hold both number 2 and 3? It depends on wether you want to judge a clan on individual skills or on all-round adverage skills.
Now, I'm not saying any of these clans are bad. Quite the opposite is true. These 3 clans are the only clans on their level, the only clans to really challenge one of them are the other 2 clans. They are really good and their players are all very skilled at WL.