Another really good amp simulation plug in system (already mentioned by Darryl) which is one the very first ones out there giving the guitarist a very direct, non-software-like feel on playing is the Positive Grid Bias Amp/Fx plug in.
I have had tested and heard tons of amp sim plug ins (from Amplitube, Brainworx, UA Unison, Eleven all versions etc.) over the years but the Bias Amp plug in provided the most accurate "guitar-feeling" of all those amp sim plug ins.
The great thing with the Positive Grid stuff is that you can start with only the Bias Amp Standard and the Bias FX Standard plug ins each for $49.- only at the moment and even keep using your current audio interface.
If you got any money later (or you will have saved some in the future) you can go and buy the Bias Amp Head or the Bias Rack hardware which will be the suiting hardware to your Bias Amp software sim.
Whichever amp sounds you may have found and played with with the Bias Amp plug in before you then can load into the hardware and use for gigging etc. Means you will not lose any of your favorite amp sounds but you only will be
able to expand your options.
There you can find the Bias Amp Standard version for $49.-
https://www.positivegrid.com/bias-amp/
https://store.positivegrid.com/?_ga=...anchor-biasamp
There you can find the Bias FX Standard version for another $49.-
https://www.positivegrid.com/bias-fx/
https://store.positivegrid.com/?_ga=...#anchor-biasfx
With these two you definitely have all you need to start. You may import all the amps from the Bias Amp software into the Bias FX software which can be done by a simple click within the Bias FX plug in and you are good to go.
You know, you want both, the Bias Amp Standard as well as the Bias FX Standard just because in the Bias Amp plug in there are the better sounding amp sims but there are no effects which you will find in the Bias FX plug in finally.
Get both, use it together and you will get a very decent set of guitar sounds for about $100.-.
As mentioned before you can expand your system with the Bias Amp Head or Rack hardware later where you can load into all your favorite amp sounds you have played with over the years before (with the Bias Amp plug in) and
you even can print/sample your hardware amps if you would want to like with the Kemper system.
The Positive Grid Amp system is very similar to the Kemper but with the Positive Grid Bias Amp/Fx etc. plug ins you can start out already without having to spend an arm and a leg for the whole hardware system yet having all the
sounds you may use later on with the hardware too.
One important, crucial thing at amp sim-recording always has been low latency. You definitely have to use buffer sizes not higher than 128 samples, to be honest, 64 samples would be accurate to play/record decent guitar tracks.
Means, if your Behringer audio interface does not allow for at least 128 samples without any problems and artifacts you will have to check out another audio interface. As mentioned before, if you can use 64 it would be a lot better.
It of course depends on the power of the processor of your iMac as well how low you can go with the latency at the end of the day but you might consider getting this little box instead of your Behringer too. It not only operates on
another level as for the sound quality of the converters and the mic pres, as I have seen at friends the 2nd Gen of these boxes allows for 64 samples most of the time even with many other tracks in the session already.
So this little interface is kinda bargain for what itīs offering. Further it does work well with PT12 as well as with all the latest versions of macOS and with Macs it does need no driver at all=no driver issues, which is very nice indeed.
https://www.sweetwater.com/store/detail/Scarlet2i2G2
You see, for about $250.- you could get a completely new, modern guitar recording set up for your Pro Tools/Mac system which you easily could expand later with the Positive Grid Bias Amp hardware (Bias Amp Head or Rack) for
live or studio applications.
Rack
https://www.positivegrid.com/bias-rack/
https://www.sweetwater.com/store/detail/BiasRack
Head
https://www.positivegrid.com/bias-head/
https://www.sweetwater.com/store/detail/BiasHead
Yeah, btw they offer an additional Metal Signature Pack for again $49.- at the moment if you would be interested.
https://store.positivegrid.com/?_ga=...649.1513317362
(you may scroll down a bit to find it posted on the left side down there)
However, from my personal experience you will find enough decent stuff in one of the two Standard Packs for sure. This might be an additional option only.
Anyways. So I hope you will find the system which suits you best at the end of the day.
All the best to you,
VRW