Both brands tend to get very polarized opinions - you either love their stuff, or hate it.
It's very subjective, but here it goes: I went from Ibbys to Warwicks, and after a couple of years I've switched back to Ibanez. IMO they offer the best bang for the buck.
SR600 is a proper Ibanez SR. Warwick RBs are cheaper (budget) versions of their expensive models - it's what Squier is for Fender. That doesn't mean they sound bad, but on the other hand, that does mean they don't sound like the real deal. All in all, you shouldn't decide without testing the basses in person - they sound quite different: 'Vettes tend to sound a bit more classic (Fender-ish...dare I say), while the SR600 has a warm bassy tone. I guess both would do a pretty good job at covering those music styles.
The Ibanez Club #143 | The Soundgear Club #12