There are valid reasons to buy any of these guitars (although personally I think the RG550 is a good choice, well balanced instrument with some wiggle room for customising).
The only real piece of advice I can give is to play them. One thing I have found with guitars, is that I knew immediately when I struck a guitar that was right. Interestingly, there were times I could try half a dozen of the same model and it was only one of them that felt right, usually the right one was the wrong colour, lol. (I used to sell guitars many many years ago, so I got to setup and play hundreds).
One example of this that sticks in my mind was an EMG-loaded ESP neck-thru that I played. I never liked any of the previous ESP's we'd had in stock and I've always hated EMG pickups, but this one particular ESP that came through just blew me away, I really bonded with that guitar, played it every day and it killed me selling it.
The money you are talking about is not insignificant. Think of it like buying a car, would you buy one without driving it first or at least the dealer demo? Maybe a road trip to a decent Ibanez dealer is in order, spend the day playing different brands/models and see which ones resonate with you. (pun intended).
I hope whatever you choose makes you happy after all that's what really matters, let us know how you go and post some pics