i would say (and this is totally MY personal opinion) that since you're pretty new to this game, set your sights slightly lower at this time. the 550 (and 1550/1570) are all excellent guitars, no questions asked, but do you need to be spending $900 straight away.
id been playing for 3 or 4 years before i got my first ibanez. is a '99 RG450DX, and its done me proud for 12years. the neck isnt quite as thin as a 550, the stock pickups arent as good, and the trem doesnt even begin to compare to the edge/lo-pro, but ive still been able to play along to maiden, metallica, vai, etc to a pretty competent level.
now ive just invested in a 570 and 750, because i feel im at the skill and knowledge level to appreciate and realise what the differences are between all of these.
as a relative newbie, id suggest to you to maybe look at something more along the lines of the RG350s, or a MUCH lower priced used 550 or similar. this way, if you decide in a few months time that actually learning the guitar isnt for you, you wont have laid down best part of $1k for no good reason.
not trying to be a kill joy or a scrooge at all, just want to be a voice of reason!
good luck with whatever you decide on tho!