Sort of a biased question because this is the BLOCKLAND Forums, but what the heck. Go ahead, answer it. I do not relate the two because they are completely different other than the "build andything" philosophy.
Here's a list I made to help you make your mind up:
Minecraft
Pros: Better than infinite mining. AI is better. You don't have to fiddle with minigames. Huge, custom maps with much more space than Blockland maps.
Cons: 16 bit graphics. Laggy on most computers. Buggy. Slow multiplayer with seperate server launcher.
Blockland
Pros: Way better graphics. Better multiplayer. Virtually no bugs. More features. You don't have to enter IPs to enter a server.
Cons: No good survival minigame with all of the features of Minecraft. Can't get new texture packs.