We've visited Universal and Walt Disney World each twice over President's Day week. My advice, based on our personal experiences, would be:
1 - Avoid Walt Disney World on a holiday week at all costs. Disney is a nightmare when crowds are high, and the only way to avoid it is to pay for
Genie+, which everyone else will be doing too, thus largely destroying its value. In our two experiences during this particular week, we've found that Disney will
not increase hours or ride capacity to deal with February break crowds: it's treated like every other week in February, and guests will simply be made to wait longer for everything. After getting burned twice with February visits, we've sworn off of them altogether, and will not visit Disney World except during less-popular times of year.
2- Universal is a completely different animal, with a skip-the-line system that is better managed and scaled than Disney's, and it is possible for impatient people like my family to have a fantastic time there even during February break. Stay at a Premium hotel or purchase Express Pass, to make your touring more stress-free. Be reconciled to the fact that you may have to wait 40-60 minutes for a few attractions (e.g., Hagrid's, Minions, Velocicoaster, Spiderman), although this can be ameliorated by visiting those attractions first thing in the morning or last thing at night. Otherwise, your waits should be fairly short -- longer, perhaps, than if you visited on a non-holiday week, but still very reasonable (in our experience, no more than 10-20 minutes for most attractions).
3 - President's Day week is a holiday for much of the northeast, but locals will also have Monday off, and many of them will spend the long weekend at the parks before heading back to school on Tuesday. This means that the biggest surge is from Saturday-Monday, with crowds diminishing a bit on Tuesday and continuing to peter out slightly as the week goes on. If you're not planning on being in Orlando for the entire week, push your trip (or at least, your park days) as far into President's Day week as you can.