I was very interested in it for a couple of weeks, but then I stopped playing much. Once in a while, I get in a mood to add onto my subterranean underworld and fire it up again. Still need to finish my underground biodome and Nether castle.
I wish the engine wasn't so inefficient. Disassembly shows some cringe-worthy code. This kind of game should run on netbooks, yet areas are choppy even on high-end machines. The pixel art also starts hurting my eyes after a while. Interpolation would help a lot. While higher-resolution texture packs help, they also risk breaking after updates.
Yes, there's definitely some inefficient code - but voxel-type games like this are also legitimately computationally difficult. Just because it looks like pixels doesn't mean it's simple to run.
There are occasional engine improvements, but Notch thinks (as he says in that reddit thread and elsewhere) that players don't appreciate changes that aren't new features.
Also, my machine is mid-range at best, and I never have any problems. In Windows of course - Mac and Linux are quite a different story. Then again, you could say the fact that it runs in other OSes at all is impressive.
OpenGL on Java is still pretty immature. There's still plenty of issues with the library Minecraft uses, LJWGL, especially on Mac and Linux. Support for OpenGL itself on non-Windows OSes is also often lacking, especially on ATI or Intel graphics cards.
I wish the engine wasn't so inefficient. Disassembly shows some cringe-worthy code. This kind of game should run on netbooks, yet areas are choppy even on high-end machines. The pixel art also starts hurting my eyes after a while. Interpolation would help a lot. While higher-resolution texture packs help, they also risk breaking after updates.