Just a tip (sorry if I'm repeating):
Consider buying a seasonal annual pass, especially if you plan to visit during a non-holiday time of year when annual passholder hotel discounts are likely to be offered. For my family of four, buying 2-park seasonal annual passes cost something like $20 more per person than the 4-day park-to-park tickets we were considering, AND I was able to book a Universal deluxe (Hard Rock Hotel) at about $250 per night after passholder discounts came out for our visit dates. (I'd initially booked at Royal Pacific for over $300/night at the "stay more save more" rate because we wanted to get the unlimited express pass benefits and were hoping that APH rates would eventually come out for that hotel, but APH rates weren't released at Royal Pacific for all of our dates, so Hard Rock became the least expensive option even though it typically has a higher rack rate than Royal Pacific).
So by buying APH and paying $80 more than we otherwise would have for our park tickets, we saved $165 on our hotel stay cost even though we ended up at a more "expensive" hotel, which give us the unlimited express pass for our stay. Not only that, but if we want to come back within a year of our first use of the seasonal APH (subject to blackout dates, although they're mainly for the month of July and for major holidays when we wouldn't want to travel anyway!), we won't have to pay for park tickets. Total win-win and I'd recommend it to anybody.