Just chipping in that I have been going for the past three years during the week before Presidents Day and it has been great (even 2013 when I was there on Mardi Gras); crowds not bad at all, resort rates as low as they get, and when the weather is nice, it's beautiful. I had a couple of COLD mornings in 2012 and a couple of days in 2014 that dripped rain off and on, but for the most part weather was lovely, temps in the 70s, very comfortable.
I have only two negatives with February: One is, I miss Splash Mountain (down for refurb in 2013 and 2014, and the only reason it was open in 2012 was because BTMRR was closed for a lengthy refurb at the time). The other is, I hate hate hate driving in any winter precip, and I worry about getting back and forth to my home airport. Since Easter is so early next year (April 5) I'm actually looking at April 18-24 for my dates in 2015. We'll see.