Is it really worth buying the Universal Express pass for Universal Studio Orlando?

We are planning to visit Orlando parks (Islands of Adventure and Universal Studios Florida) at the first week of this April and don’t know is it worth considering buying Orlando “Free pass” (fast line-up ) at popular attractions. Is it?

We were at Disney Paris last year and used the “free pass” (no need to pay for it) and it was worth, but still some of the facilities we waited for one-two hours at line. We visit each park all day, but the park was closed very early, about 6–7 fm.

Does April month is a busy season in these parks? Should we spend money on that?