I think it all comes down to who you are as a gamer.
If you're a self-proclaimed Nintendo fan, then yes, definitely an excellent purchase this holiday. $299 is an acceptable price (maybe even cheaper if you're lucky), Mario 3D Land looks stellar and the backlog consisting of Mario U, Luigi U, Pikmin 3, Wind Waker HD and the Wonderful 101 (not to mention the excellent Rayman Legends) is much more appealing than everything that'll be on the new consoles this year put together (my opinion).
If you're someone who likes at least some of Nintendo's properties, then I would say it's a good buy this year, but you may want to wait until next year which is going to be spectacular for the console. Jump in for sure when it becomes $50 cheaper.
If you're not really a Nintendo fan but don't have an aversion to them either and still consider yourself a gamer who wants to experience everything, then enjoy your PS4/XB1 for the foreseeable future but pick up a WiiU eventually; probably near the end of its life for $199 or less with a huge backlog for cheap.
If you don't like Nintendo's games and never cared about Nintendo consoles in the past, then obviously the WiiU is not and will never be for you.