Ah, totally forgot about the neck on the RG2550. Nice three piece glued maple with volute. (Folute is kinda ski jump bulge sticking out on back of the neck). The volute is intended to give the neck little more mass in critical top part of neck (where neck is the thinest.) Some like this feature (me included) some hate it. Three piece necks are considered stronger than one piece necks. Neck is less prone to warping.
Older RG's have truss rod AND bolds for top lock nut drilled in area where neck is thinest and weakest. That's why you see some older RG's with neck problems. RG2550 neck is one of thinest and most comfortable. (if you like thin necks, but if you didn't you wouldn't be looking at a RG, I guess)
About the trem......tons of pages have been written on the Edge, Lo Pro Egde and Edge Pro trems. The new trem has gotten some bad press at the beginning of introduction. (Just type in Egde Pro on this forum and you can read some interesting posts.) Most problems have been taken care off.
Some people always will be die-hard Edge, or Lo Pro Edge users.........that's what they used to. They like the feel and performance of "their" trem.......that's probably why Joe and Steve still use the older types.
That the new trem feels little different from their old Edge trem, doesn't make it a bad trem. It's just one great looking and performing trem.
And yes, it doesn't have the lock nuts......but if you want them in, you can easily fix that yourself. See Rich pages on this on www.ibanezrules.com
Together with the Kahler and the Ibanez ZR trem, the Edge Pro is one of my most favorite trems.
Just my $0.02