I hear a couple of things going on here...
First: Amp modelers (i.e. Line 6 Spider, Peavey Vyper) are to expansive and complicated, Boss GT series way to tweekable and complex.
Second: Tech 21 and Behringer "modelers" have a simple enough interface, but do not cover enough "models."
So, what is desired here is a modeler with an interface that is simple like the Behringer GMX series, with maybe, 7 to 9 (?) amp models (instead of 3). Doesn't have to be digital, though digital is easier to get the nuances closer to the real thing. Am I on the right track?
Now, I don't have an ear that can hear much difference between two 12AX7 tubes, but what I have found and in my opinion, the Digitech RP series seem to have the simplest interface. For the amp modeling, you just select the amp, and the gian level and away you go... Newer ones (70, 90, 500, 1000) have a switch to turn on and off the cab modeling (4x12 Greenback, 4x10 Jensen, etc.) to go with the amp model you select, and they sound prety damn good, in my opinion. It is true, that with the streamlining of the interface (RP70/90) that they are not a flexable as others... but it sound like that is sorta what you are looking for. I have owned several of these, RP80 was my first, then an RP70, then RP90, now an RP55 (repackaged RP50)... I would love to have an RP1000 they seem to be the most flexable with the inclusion of an effects loop, somewhat selectable effects positioning and a few "stomp box" style effect-on/off type switching. All in all, a very nice floor box, to be sure.
There is a "but" to all of this amp modeling... How do you actually get the sound of a Marshall going into a pair of 4x12s out of an 8" to 12" single speaker, "custom" voiced guitar amp? Well, you can't, period. So, since I am a not so great player, I am a fairly avid reader, I have read some interesting things from Tom Scholz (Boston) that make me go, hmmmmm. Most importantly, in his mind, is that the amplifier and speakers be "full-range", meaning they be more like a stereo system than a guitar amp (full frequency as opposed to limited frequency response). If you have read a Sustainor manual, or seen the Rockman Stack amp setup, it reccomends that you use a "full range" set of speakers (his had a 15" woofer, 8" or 10" midrange and a horn/peizo tweeter) and a massive stereo amp (Carver 1.5t field effect 500 watt) for headroom. Clean guitar signals require about 3 times the amp power as a distorted signal for the same volume... sorry for the rant, back on topic.
Any way, what I am getting at is using an amp modeler with a guitar amp is not going to get you the sound of a JCM800. I think that this is one of the main reason that most people are dissapointed in the floor-style modelers (and amp-style, for that matter). But, if you are adventureous enough to connect your pedal style modeler (RP90 etc.) into your home stereo, and turn on the cabinet modeling, you might find the sound is prety darn close to the "amp" you have selected to play through. Just make sure that the volume is low enough that your amp has some headroom to play with, without clipping (home stereo amps and speakers don't like to be overdriven like guitar amps do!).
Anyway, just some thoughts on the subject... I hope I haven't bored everyone out of the discussion.
"...and I am outta here!"
Scott
Guitars:
Dean EVO Exotic Burl, EVO Special, Vendetta 1000 FR, Stagg Les Paul copy, Squier Standard Telecaster, Squier MIK Stratocaster
Amps:
Fender Princeton 65 (solid state), Vox AD15VT, Peavey Windsor Studio, Crate Vintage Club 50 2x12
Pedals:
DOD FX40B (x2), FX50, FX52, FX55, FX65, FX67, FX80
Washburn LSESLD, LSBOD
BBE Free Fuzz
Behringer EM300, VP1, PH9
Dunlop GCB-95
ProCo Rat II "The Rat"
DigiTech Bad Monkey, RP90
Rockman Soloist
and many, many, many more!