I'm a big proponent of modeling amps! I gigged with a Johnson Millennium for over five years, and it's coming back out A/B'ed with my Germino with the new band.
In short - I love my Johnson amps. They're capable of pretty much any sound you can imagine..........IF you have the patience to dig through 17 pages of editing on the amp. They're not for technophobes. They do, however, reward patient tweaking.
Modeling amps are godsends for those playing covers and needing to cover lots of sonic ground. Just do your homework tweaking the patches, load them in memory, and stomp the right switch when you need it. They make gigs an easy affair when it comes to running your rig.
There are downsides to every modeling amp, however.......................
Regardless of how much you dig and tweak, they're only going to sound "close". The digital technology has not crossed over to meet the touch response and nuances of those sought after amps. On gigs. however, "close" will pay the bills. Nobody will notice.
If you're a tone purist seeking those absolutely pure vintage tones, don't look to modelers for it. Play the real thing.
If you're a player seeking a huge spectrum of sound with one amp and are not too hung up on all of the nuances, then a modeling amp might be your thing.
I can go on, but this enough for one post............
Guitars: 2008 Gibson SG Classic, 2006 Gibson Les Paul Standard LE, 2002 Gibson SG Supreme, 2001 Gibson Les Paul Studio Plus, 1996 Les Paul Studio Gem, American Deluxe Double Fat Strat, Bluesville "Super" Strat Copy, MIK Fender "Limited Edition" Tele, JD Bluesville "Night Pilot", Yamaha AES 820, Steinberger Spirit GT Pro, Taylor 355CE, Ovation 1897 Adamas, Ovation CC057 Celebrity
Amps: Axe FX centered rack rig, Mesa 4x12 cab. Germino Club 40, Johnson JM150 Millennium, Johnson JM250 Millennium, Gibson Titan Medalist Frankenstein.
Effects: Tonebone Trimode, EH Holy Grail, Boss CH-1, Dunlop Crybaby Classic, Framptone Amp Switcher, THD Hot Plate, Yamaha AG Stomp Acoustic Processor, Boss BCB-60 Pedal Board.