Hi
Welcome to the dark side.
I was about to say the exact same thing!
Only have experience with Cabana Bay but it's head & shoulders over Disney buses at Universal. They ROLL those busses one right after the other! Fantastic service across several visits. We haven't stayed at either of the Endless Summer resorts but reviews say it's the same there.
This is where Universal absolutely KILLS WDW. We went for the first time last October and I couldn't believe how fast they were. After spending alls, I remember going back to the Cabana Bay bus stop and seeing a huge line of people. My instant "Disney hat" went on and I started to bellyache. I said, "It'll take at least 4 buses to come and get the crowd in front of us." Thinking Disney, that's at least a half hour of waiting or more. But in less than 10 minutes, 4 buses had cleaned up the line and another bus was waiting for the people who'd come behind us. At that point, I was hooked on Universal.
We did 4 days at Universal, with tickets to all 3 parks. That was just about perfect, as we spent one full day at Volcano Bay. Don't know if you like water parks, but this one is without a doubt the best in the world. We loved that place. And we'll be doing it again in December no matter how cold it is. If you do just the main parks, 3 days should do ya if you have park-to-park tickets.
For the best times, think Disney. It's the same pretty much. Though I'm curious to see what an off-season visit is really like. It may be way better than WDW, which doesn't have much of an offseason anymore.
We stayed at Cabana Bay and will again because they have rooms that fit 5, plus they're right next door to Volcano Bay.
As far as restaurants go, no need for a car to head around town. The parks and City Walk have plenty of great places to eat. And if you aint diabetic, head over to Voodoo donuts for something that will put your tastebuds into shock.
Have fun! And welcome to the dark side.