I waited long before buying this. I've watched the development from day 1, tested the "unofficial" version and finally decided it's time.
Considering i spent literally lots of hundreds of hours in the Dungeon Keepers, and adding the confidence, commitment and love the developers show for their project, i can safely predict what this will become: GLORIOUS!
It looks and feels almoust identical, except the modern graphics of course. Well, modern is not quite right. It still looks dated, but not compared to that old original DKs. Well does that matter? HELL NO! It's more than adequate and gameplay > graphics!
Although WFTO tries to clone DK in every aspect legally possible (even the "...has entered your dungeons"-voiceover had exactly the same melody) i've notices some minor additions that won't change gameplay but makes it more fluid. Like different rallies for workers (YAY!) and warrios. Or a flag to forbid workers to dig there (YAY!) or groupings (YAY!).
Why reinvent the wheel? It already was perfect.
Sure, a recommendation based on a tutorial and a sandbox is quite risky (as there is not much of a campaign here yet), the basic gameplay-skeleton looks and feels "right".
THIS IS THE SUCCESSOR WE'VE ALL BEEN WAITING FOR TOO LONG!
Even if it does not add much new things, it revives one of the best game/gamplays of all times. Although i still play DK2, this will end an era and start a new.
What about Dwelvers? They're damn brilliant too, and even a lot cheaper. But they're having a different approach. Taking the master and bringing in their own vision. This is totally fun too, but it's not DK3. Not visually and not gameplay-wise.
Get then both if you can!
If you can't, get this one if you prefer the "darker" original gamplay and get Dwelvers if you want some creative fresh ideas added to an already superb gameplayconcept.
You're into RTS? You like a game that does not take itself damn serious? You're quite fed being the "good" fighting the oh-so-bad? Give this one a try! But only if you think this will really suit you, otherwise WAIT until it's done! Without the campaign you'll stuck with the sandbox. The campaign will decide it's final faith (and multiplayer of course).
Alternative? Except the masters itself, there is only Dwelvers. Maybe "Dungeons 2" (time will tell). Besides there are no games (to my knowledge) that come even close to this gameplay and fun. Period.