+1 to money being a consideration.
I'm opposite of Solarmist though...
Easy (for me anyway)... The Warwick. But I'm a little biased, the very first bass I ever played was a Warwick (Dolphin Pro
) for about a year on tour with a bassist who was kind enough to take me under his wing (I was a sax player at the time). I've also played a Corvette and Thumb. On the Ibanez side, I still own my first bass, an SR400 and owned an SR535 for a while. I keep the 400 because it was my first bass, I haven't played it really at all since moving to 5's about 10 years ago.
I personally like the sound of the Warwicks better, but that's purely subjective of course. I do think the electronics in the Ibanez basses weren't as good and for me, the more organic warmer tone of the Warwicks were more usable. The SR's, particularly the 535, had a more modern tone that was too bright for my applications. I often found myself dialing the treble way back, and in some cases not being able to dial enough out.
Another thing I didn't like about the SR535 was the inset input jack. I use straight/right angle cables with all my other basses, but the 535 required me to flip the cables around. Not a big deal. However, there isn't much space between the bass and the cable, so I always had a little trouble pulling the cable (Monster Bass, with somewhat chunky plugs) out by the plug rather than having to use the cable itself. Course, I don't exactly have delicate hands.
Necks are also definitely a consideration... The SR's have a fairly fast, thin neck where the Warwicks are a little thicker. Both feel nice, but I prefer the Warwick necks.
As with all any gear choice, the best suggestion is to play both and decide for yourself if you can. What someone else loves, you may hate.