Yeah alot of people complain about the Edge Pro but the EdgePro on my RG1550 is great. It rarely goes out of tune even with the craziest whammybar antics. The only thing that wacks it out of tune is pushing really hard to make strings go sharp, but that's because mine isn't setup very well
I don't even have a locking stud mod on mine
For divebombs, flutters and... well everything, the Edge Pro really does perform. I had the pleasure of trying out a new UV777 with the EdgePro7 and i thought it was a nice trem. It didn't stay in tune very well when i played it, but that's just because the guitar wasn't setup by the store (as most guitars in stores arn't - lazy shopowners!
). The guys at the store told me it wasn't setup but if it was it'd stay intune, and judging from my RG1550 i believed them. It still stayed in tune quite well, with a set of .9s on it.
My RG7420 is absolutely terrible for tunning stability - Lo-tres7. It used to be quite good, but it's just not getting any better. I guess it desperatly needs a pro setup because it's been beaten up and knackered for 2 years straight.
I've blocked the trem of and i'm about to put a set of .11s on it. I'm going to use it as a hardtail with fine tunners (a valuable thing on any 7-string hardtail. I just wish Ibanez brought out a 7-string with an FX bridge).
I do know a few people in my area who have bought RG1527. I'll have to get together with them and try it out.
Though if there's one thing Ibanez don't do well - It's pickups. The pickups on my 7-string are very muddy. I guess that the RG1527 is probably the same. IBZ pickups just don't cut it