actually, Steve Vai uses the ibanez... though not the RG Series, he uses the 7-string ones...
Now if you like:
Hmm i play blues, old sch metal and a little of rock.
It's different angles,
if you like blues, fenders are used by Eric Clapton and Fenders have a richer tone to it. But then if you like the warm tones, then go for Gibsons.
But when you like old sch metal, then a Fender won't do so good, becos of the lag of Floyd Rose that deters your whammy tricks, and probably the 22 only number of frets that Fenders are stuck with, on the contrary, Ibanez have 24 frets which makes it easier to shred. If you are keen on metal rhythms, then get those Rosewood fretboards, Ibanez RG Series have both the Maple and the Rosewood versions, while Fenders are mostly fixated to Maples. Basically, Fenders are not really right for metal, so to speak, while ibanez were all intended for metal and heavy rock.
I think it really lies with what you weigh as more important to you as blues, metal and rock have a differing range.
If blues is important, go for Gibsons.
If metal, then go for ibanez or you can check on Hamer at Davis.
If rock, then it's a question of what you want to do, rhythm or leads. if Leads, go for ibanez, if rhythm, go for Fenders