Been a few times, and stayed in a villa each time, on the basis that we’d eat out each night anyway, and the extra space and private pool would be good for our sanity.
Top tip for Disney is to get your FastPass+ set-up on your tickets before you go. You can schedule three major rides per day in advance, plus on-site restaurants (which get full at lunchtime inevitably, so this is vital for an air conditioned sit-down – food is generally very average in Disney though). The iOS or Android app (parks have free wifi) tracks waiting times, so is pretty useful to have. Disney penalises the disorganised.
Universal is better than Disney IMO, but doesn’t have the FastPass+ system (unless you pay through the nose). The Harry Potter area is rammed in the morning, but really quietens down by evening. Apps for waiting times also useful.
Attraction Tickets Direct are who we’ve used for tickets. Next day delivery.