I had the Amplifire, now have the AX8 and Helix.
The Atomic unit was nice but when I first used it live, it was VERY "ice-picky" sounding through the sound system, which is not what I heard at home of course, but at the time I ran it through the power-amp in of a Fender HRD which shouldn't have colored the tone TOO much. I was able to tame the high end, but it didn't seem to play well with our FOH as the Fractal. Also, its more limited with FX and you really need an external MIDI device if you want easier switching. It was my first try in the "modeler" world, and it WAS a cool box, especially for the price and I might have had a better experience if I had used an FRFR monitor. I bet the bigger version is pretty cool. The Amplifire was overall very nice, but I am happier with the other units I have. To go back would be a step down IMO but I bet now that I have more experience I could make it work better.
I use the AX8 exclusively now to play out, along with an Atomic CLR which I got recently. It works very, very well for my needs. The pros are super amp modeling, effects and what I dial in at home is pretty much exactly what I hear from the FOH mains and monitors...the BIG deal things. The cons are (IMO) are a somewhat difficult interface on the unit itself, its pretty complicated and while the constant updates are nice, they often cause one to need to re-tweak their user presets...so you might be tweaking more than playing at certain times. Of course one doesn't HAVE to update the unit, but I bet everyone does, eventually. I have mounted the AX8, a volume pedal, wah and a Line 6 wireless receiver to a board, and my setup couldn't be much easier.
Current AX8 setup...set board down, take off top, plug in AC, plug in FOH, plug in FRFR monitor (if needed) done.
When I used the Amplifier...not as easy but not too bad:
The Helix was an impulse buy to try. Its pretty easy to use, but IMO, the stock IRs are not great and the high gain tones aren't as nice as the Fractal. I bought a pack of presets from some guy who sells them (Fremen I think), and they came with custom IRs. After looking at using some of those presets, I am better able to get some great high gain tones, but the variety simply isn't as vast as the Fractal. In the end though, I am not sure just HOW MANY amp models you need...I tend to find a great clean and a high gain model and tweak those to get everything I need. Hence I think eventually I could get the Helix to work for me if I wanted. I also believe it has more processing power than does the AX8 so you can really load up a preset with tons of stuff. For me, that means I can have LESS presets, and each one does more. Also, the built-in expression pedal is cool (hey, it does the Whammy thing!!). I've not dialed it in to play live yet...it also lacks a "talk box" type effect which is something I always have to have as we play that damn Bon Jovi song every gig. So I'd have to drag along my talk box if I really wanted to do it right.
In the end one will work better than the others and its fun to find out which.
