I'm a UK visitor and we did a trip this August for 8 days, spending 2 days at Universal and 6 at Disney. After upgrading our 2 week £120 (Approx $180) Universal tickets to Universal Power Pass AP's for $30, we are heading back for 2 weeks of JUST Universal in Feb 2016. We're staying 2 weeks at Cabana Bay for about £750 ALL IN after discounts (Approx $1200).
We went to Guest Services at Disney and were told that it would cost us about $400 to upgrade our 2 week Disney tickets to AP's, which is a hell of a lot more money (That's before the current rise too).
I'll be honest, I am mostly SO looking forward to not having to plan 14 days of which park I will be at on which day, having to wake up at 05:00 UK time to book Fast Passes, make sure we're up for rope drop every day to ensure we get on a decent amount of rides etc. I'm just gonna chill and not feel guilty when we need a pool day to recover!
A small part of me will probably find it strange to have made such a long journey and not head to WDW even once, but I think that financially and from a POV of just 'felling like it's a vacation instead of a military planned operation', I think our future now lies exclusively with Uni, with Disney maybe done every 3 years, or after a new major attraction opens there (which could be even longer!).