Let me make a bold statement. Guitar amp emulators are now so good that long-time tube amp users are switching over, at least for live playing on-stage. If you think that statement is blasphemy (and I can’t believe I’m making it myself), then you should watch this behind-the-scenes video of the live guitar rig setups for James Hetfield and Kirk Hammett of Metallica. It’s an eye opener.
Both guitarists have nearly identical setups that center around Fractal Audio Axe-FxII XL+ guitar preamplifiers/processors, which are then fed into Matrix Amplification solid-state (!) amps for on-stage monitoring. The house console feed comes directly from the Axe-FX. The wireless setup is pretty extensive and interesting too, as well as the cool little analog box in between everything that makes it all work (now you have to watch).
We’re now living in a new era were tube amps are used more for recording than live, and Metallica is a great example. If you can get relatively the same sound with more control and the same sound every night like you can with an emulator (and without the hassles that tube amps bring), then you’ll probably see more major players going this direction in the future.