I know I'll sound like a fanboy, but in my view Digital Performer smokes Cubase in terms of ease of use and also in sound quality.
I have Cubase (and Pro Tools, and Logic) but Cubase just seems to require too many extra steps to accomplish what I can so quickly do in DP. Particularly when it comes to VI's and effects..it should be easier to launch a VI, insert an effect, or add a track in Cubase, but it isn't compared to the other DAW's. Steinberg keeps adding features to it but a lot of the features just make it more bloated and bog you down with too many options.
I know..mention Digital Performer and a lot of people are like "huh?" But it remains the number one DAW for film composers, and for good reason. Pete Townshend, Paul McCartney, and Phil Collins have all used it, so it must be good enough for them...fact is, it really works like an old school tape recorder, very simple, and it has one feature no other DAW, including Cubase, has...the Tracks Overview window, where you can see all your audio tracks, Midi tracks, aux tracks, and master faders in the same window at the same time.
You can demo Digital Performer free..works both in Windows and Mac..
http://www.motu.com