The GNX3000 may be out of production, but it still holds it's own, and may even still surpass Digitech's latest offerings. The 3000 introduced "component modeling" where each electronic and mechanical component of an amp or cabinet was individually "modeled" to create the overall tone close to the orginal (when mic'd that is). No one would ever confuse any modeler for the real thing just plugged into a studio monitor. But mic it into a PA or in a recording and it's very close. Close enough that you would probably chalk up differences to technique or recording set up.
I say it may surpass Digitech's latest, but it's hard to say because, frankly, the demo's on their site for the new gear are so lame. They need to borrow a page from Line 6 and hire some great guitarists for demos.