I don't bother with Surecast, but if you don't take it you probably won't be filling up all your cross class skills so it's worth taking. I probably should use it, I'm not sure if it prevents being interrupted from things like Garuda's Reckoning (I think in HM or something it interrupts casts) but if it does that makes it a must have.

The main ones are Swiftcast, Virus, and Eye for an Eye