We have been 3 times in February (our anniversary). While the weather can be unpredictable, it's always been much nicer than it is in Kansas City in February. We always choose the first week or two as it's the value season (prices go up due to President's Day holiday and into spring break season). The parks aren't usually open very late at that time of the year, but with the attendance lower, we never have a problem getting to everything we want to do. The prices are lower, lower attendance, better weather than what we have at home (has even been warm enough to swim once or twice).
We're booked for Feb 2 - Feb 10th at Pop Century right now, but we'll see if any AP rates come out later this year for those dates, but wanted to get the trip on the books and start getting it paid off prior.
If you decide to go, I don't think you'll be disappointed. Just keep an eye on the weather forecast before you go, so you'll pack appropriately.