Hm, it's neat but it's not a game that plays well under the notion of a time constraint. Like, it's a relaxing kind of organic experience - but that's kind of undermined by the idea you only have a few days to give it a shot lol.
Plot claims seem HUGE relative to the size of the map (and what most player's will actually construct I think), maybe that varies by server though. I think part of the intent is so that one person's "construction" doesn't impede on another person's borders or even their 'view', but I think it'll ultimately amount to a lot of empty, unclaimable space.
Mining, harvesting, exploring are all pretty cool - there's something to be said for simply having fun "gearing up" as it were - especially with some of the neat accessory items that you can make (ring to find rare materials more often, boots that make you run faster, amulet that makes you jump higher, etc). A click "lock" would be really helpful though - rather than having to spam click or hold M1 the whole time.
Haven't done much of any 'building' stuff yet, aside from placing some blocks to jump out of some mining holes.
I don't think I'd ever end up building the Taj Mahal, but it's a nice change of pace from the feeling you typically get from an online game.