I have had all three, I have the System and the Major still, the Force replaced by eventide dsp4500.
Major is better than most of the digitech and zoom types in the sub $500 ranges, not mutch to edit per effect, just a few minor adjustments, like having stomp box effects, but not bad over all for the price. The DAC's are not as good as the other more expensive models and the effects input output section is lacking in control, but if you are looking for the basics of delay, chorus, phaser, simple pitch shift, and a simple compressor you can't go wrong with it being stereo too. Best used in the effects loop (preferably a stereo setup)
G System is great and compairs sound wise with the Force however it is NOT as flexable or TWEAKABLE as the force, again like the Major it's more like having a bunch of stomp boxes however these are GREAT stomp boxes, a great buy for the fact of loop/switching and pedal controls built in one unit. Better pitch shift than the Major (smart) and a few more settings than the Major as far as contouring the sounds but still pretty simple over all. Most sounds are damned nice (except distortion)(good before amp and in the loop)
Force, HIGHLY configurable, a tweakers paradise coming from TC with mulitple controls and lush sounds. Yes it's starting to age a bit but it was so far ahead when released it still sounds GREAT today, not cheap even used and you still need a controller but if you REALLY want to dial in some tweaked sounds just for you then it's a choice before moving up to Eventide rack stuff. (best in the loop)
(just for laughs I add this)
Eventide DSP4500, SOUNDS INCREDIBLE, PAIN IN THE BUTT TO PROGRAM and control, not really a true multi-effect for a live situation like the TC group, it takes time to load each program etc so forget trying to do a quick change to your fav patch in a moment of tonal bliss. The sampler upgrade was cool but not really effective live as you have to pre-record the bits to play back. The looper section is nice if you have a use for it (I did which is why I got it) but you do need access to the front of the unit to controll it affectively during looping live situations. (also for the FX loop)
:!:
Those wanting just the Eventide effects and no looping etc the newer 1U spaced Eclipse is a great unit and relatively easy to use as much as the Force is and also has GREAT LUSH sounds. I did not change out to this but opted for the G System instead at the time, mainly for the built in loops for my stomp pedals (can't have enough of them) although I have a GCX 8 port switcher I wanted something a little closer to my stage position for some pedals and less cables up front over all
(last item, sorry for the length)
:idea:
If you have a bunch of stomp boxes and/or two amps and you are looking to or have all ready moved to rack effects just for the complexity of arranged presets you might want to get "The GIGRIG" instead (or in addition) not an effect pedal itself and not popular in America, yet, but I am helping the cause.
What it does is control stomp box effects as a loop switcher as well as amp outputs and channels. Depending on the model you can switch up to 10 pedals in ANY COMBINATION PER PRESET. (yes, one button to switch in and out combos of stomps and amps for complex sounds) with adjustable class A pre-amps per pre-set switch to control volume (easy boost for lead sounds). Easy programing via DIP switches as to what effects you want active per pre preset (and/or amp and channel). As good as it gets if you want those (ahem) "VINTAGE" pedal sounds using ACUTAL vintage pedals in a loop switch enviroment for no loss of tone when they are off.