Despite still having some issues undergoing development (please report bugs, devs can't test em' all), the core gameplay loop is enough to have fun with casual survival. The 0.72 release should further polish some of the existing mechanics.
For more technical players with redstone obsession, then i must warn you that the redstone system is currently borrowed from mesecons as of this review. What this mean is that you'll have to throw away some redstone knowledge from m*necraft either because of incomplete redstone implementation or not implementing redstone bugs (don't expect broken stuff like TNT duping haha). On the other hand, the redstone system is quite fun to mess around, and indeed prove to be useful to create farms and utilities. To get started, i recommend you try to relearn how everything works while keeping in mind how m*necraft's redstone work.