We bought a WiiU just for Monster Hunter (it literally gathered dust until launch day) but we're addicts.
I also bought my 3DS XL for MH, but it's turned out to be a fantastic little handheld with several other excellent titles.
It's disappointing that the WiiU really doesn't have any other stand-out games. I mean, we've had it since last fall and
still have nothing but MH for it. :/
And no, I can't think of any similar games for PC. But I've been out of the PC gaming loop for quite a while, as my decade-old hardware can't handle anything more advanced than the original Sims...