This site is still in Alpha. Meaning that stuff quite possibly is still broken and is slowly getting fixed by its one developer.
Regardless of that fact, its looking VERY promising. Its looks great, gives you tons of options, and to boot is has an amazing "combat replay" feature that lets you see all your player's movemts (warning still in very early development, so its very mild/buggy), but you can jsut see how much potential this site has and don't even get me started on their new ranking system. You can rank guilds based on how well they did on a fight compared to other guilds, you can see just how much HPS you did as a tank vs other tanks of the same spec or tanks in general, or even how much DPS you did as a healer against other players. it has great concepts and ideas and I can only see good things for this site.
Now, I'm not telling you to completely abandon WoL. WoL is so established that i fear that if people were to just stop uploading to it, the rankings would get a lot less reliable becasue of the drop of samples. On top of this site is still not even in beta, which means the developer could just very well wipe everything becasue of a bug or some other issue. (He's already done it at least once before)
What I DO want to suggest, is give it a shot. Upload your logs to both websites and see the difference. It will help you see what you like better while helping them build their data base of rankings. I plan on uploading to both WoL and WCL for as long as they both are still relevant, becasue frankly these database sites thrive on having information.
Until there can be some way to merge rankings between the two sites, if you decide to upload to one and not the other, it just lowers the quality or ranks (more so if a mass of people just stop uploading to one or the other). Quite honestly, these ranks currently on there don't mean too much, they are just fun to see because there just isn't a large enough pool of guilds uploading to it.
My hopw with this post is for people to give it a chance and take a look at it. Upload their logs and see what they think and give feedback to make it even better.