I like clones. I like ideas getting spread around. It's good for the consumers and ensures progress. But Manic Digger is just a rip-off.
It'd be awesome if they took the elements they liked and made something new and interesting with it. But they're not. They're just copying.
While I guess that is flattering, the fact that it also connects to Minecraft servers is just amazingly craptacular. So in short: Waah
By the way, they're not doing anything illegal. I strongly oppose patents and other IP nonsense, too. I just find it rude.
I appreciate the support a lot, but please don't attack their wiki!