We were at Universal during Spring Break in 2012. It was not bad at all. Nothing like the lines/crowds at Disney. But, we stayed in a Universal hotel, which made all the difference in the world. Doing so gives you front of the line privileges at every ride except HP and I think Rip Ride Rocket. And you can use it without limit in each park every day! We rarely waited more than 5 minutes to get on anything, except one time on Spiderman we waited 15 minutes. I MUCH prefer Universal's front of the line system to Disney's Fast Pass, particularly now that Disney has put SO many limitations on its new FP+ system.
If you are staying off-site, you will be stuck in the regular lines which did get quite long after mid-morning.
My advice is to spring for the cost of one of the four Universal hotels. It will be well worth it in terms of your park experience. And actually, the cost of the UA hotels (even their top one Portofino) is less than the cost of the Disney deluxe resorts during the week of April 12, which is the week before Easter.