I'm not gonna rank, but just give general thoughts on each.
John Petrucci: As the main writer of DT, it's not surprise that JP doesn't have a lot going on outside that. Still, he's 3 for 3. Both LTE albums and his solo album are terrific.
Jordan Rudess: Same as Petrucci, really, with a bit more output and a bit less consistency. I'm a big fan of LTE and his improve piano albums (Notes..., 4NYC, Christmas Sky, etc) but not so much his more prog-rock oriented ones-- though his cover album was really good. I also can't overlook his awesome work with Steve Wilson and his really innovative work in the world of keyboards in general. He seems to be like a technology pioneer of sorts.
James LaBrie: His solo albums are about on par with what I expect from solo albums, which isn't very much. But he's also got guest spots galore, and more of those are very good. Roswell Six is the only glaring weak-spot I can think of. Then again, outside of The Human Equation, nothing sticks out particularly clearly.
Mike Mangini: Not a fan of his outside work at all, really. He seems only now to finally be stepping out of his role of "session guy." Honestly, I think ADToE might be the first album he ever really "tried" on, but I'm not sure.
Mike Portnoy: Definitely has quantity going for him, but I'm oversaturated. There will always be a soft-space for Transatlantic, LTE, Neal Morse, etc, but lately Portnoy's trade-mark fills have become boring for me. Whereas I once considered everything he drummed on gold, his drumming has more of a sterilizing "been there, done that" effect on me now. Not into his cover-bands. Also, Hail! and Avenged Sevenfold were massive misfires on his part, and I fear Adrenaline Mob will be as well. He's the homerun hitter, I guess. He's hit more homers than all the guys combined-- but his batting average sure does stink!
Kevin Moore: Good work throughout FW's career, and Chroma Key is pretty good. Not a fan of OSI or his recent soundtrack stufff, though.
Charlie Dominici: Terrible music for people who think you can't get too much of a good thing
or, in this case, a bad one
.
Okay, maybe I'm being harsh on the Dominator. But still, just not into that at all