We go to Orlando every year for the last week of January - the first week of February and go to both WDW and UO. This has been our pattern for the last 7 years, so I think I've got a good grasp on the trends for both.
The quick answer is that it's still a good time of the year to go; but, crowds have been steadily trending upwards at both resorts. More so at WDW; but, UO has gotten busier over the same stretch. Weather is the usual determining factor for the local crowd deciding to come out. Over the last two years, WDW has reached the point where there is very little difference between "off season" crowds and not. UO hasn't gotten to that level; but, both parks have gotten busier over the same period of time.
I'll use two rides as a barometer of crowds during this time of the year: Pirates a MK and Hulk at IOA. When we first started our late Jan vacation schedule, Pirates would either be a walk on or a minimal line starting at the loading dock ramp. Hulk would be a less than 3 train wait to get on. The last two years, Pirates will frequently have a line out past the entrance and last year, even using a row or two of the chain queue in the plaza. Hulk the last couple of years would have a line down the ramp. My wife and my opinion, the biggest changes to both parks have been increased seasonal travelers from North America and.... the tour groups from Brazil. OU has seen a pickup from the flag brigades over the last couple of years.
The good news is that at least with UO, I would still classify both parks as "slow" during this time period. It's just no longer walk on central like it use to be.
Our trips have always included a Sunday visit to UO and usually one or more trips back during the week - typically a Friday morning in the rotation.
Sunday starts of slow with the locals abstaining until the afternoon. Things will start to pick up as the day goes along. The first few hours on Sunday are usually the lightest crowds we encounter the entire week. Friday's would tend to be more consistent in crowds during the whole course of the day. We would also make an occasional trip over from WDW on random days during that week and they would trend to be more in line with the Friday pattern than Sunday.
Each year, we've purchased the Express Pass for use on the Sunday as it is the one "full day" we plan at UO in advance and don't make any dinner reservations at WDW. Using the Pass, my wife and I hit EVERY ride in both IOA and US and have time enough repeats and see a couple of the shows. While the lines are not long during this time of the year, the Express Pass is a significant time saver that makes knocking out everything in both parks easily. You spend lots of money on your vacation, spending a bit more is well worth it.
