Sidroe
I am happiest right now with the full version of TH2.

+1

Hmmm...I don't quite get the point of blaming the monitor speakers or the guitar here.
I assume the OP has made projects both with real amps and amp sims, through the very same monitors with the same guitar (how else would he know the difference?), finding the real thing good and sims less good (??). 
If he has not, then, the alternative is he's comparing commercial recordings vs. amp sim recordings of ones own, which resets the scales, obviously. Then you have room for questions about the cabs, mics, instruments etc.
 

Kalle Rantaaho
Hmmm...I don't quite get the point of blaming the monitor speakers or the guitar here.
I assume the OP has made projects both with real amps and amp sims, through the very same monitors with the same guitar (how else would he know the difference?), finding the real thing good and sims less good (??). 
If he has not, then, the alternative is he's comparing commercial recordings vs. amp sim recordings of ones own, which resets the scales, obviously. Then you have room for questions about the cabs, mics, instruments etc.
 

Beat me to it. Amp sims are for recording, not for sounding like the real thing in your studio through your monitors. You wouldn't listen to Rory Gallagher through speakers and think "That doesn't sound like the real deal. Perhaps I need to hook my CD player to my amp cab" - lol!

I love amp sims for the same reasons I love sampled drums: less work!
 
Much of the realism that you give up isn't the kind of realism you wanted anyway. Sims don't hum or crackle or pick up radio stations. You don't care what the room sounds like. No comb filtering. No bending over the speaker to find just the right sweet spot for the microphone. No tracks blown by somebody sneezing or tripping over a cable and bringing down a boom stand.  And best of all, nobody has to drag the thing up the stairs!

Clearly, I have a lot to learn about them. I tend to think it's not my speakers as I know them so well now. I mostly use a Blackstar HT-5 using the emulated out into my OC. I am happy to use it but want to use the amp sims also. I am recording both a clean channel and the Blackstar but the clean channel ends up being archived and set aside.
 
Those of you who have good success with amp sims, does your AI have a dedicated guitar input? I wonder whether my problem is that my OC uses preamps. Inputs 1 and 2 have the button for it but I don't notice any difference in the signal I'm getting. Again, clearly I need to work with it more.

sharke

Kalle Rantaaho
Hmmm...I don't quite get the point of blaming the monitor speakers or the guitar here.
I assume the OP has made projects both with real amps and amp sims, through the very same monitors with the same guitar (how else would he know the difference?), finding the real thing good and sims less good (??). 
If he has not, then, the alternative is he's comparing commercial recordings vs. amp sim recordings of ones own, which resets the scales, obviously. Then you have room for questions about the cabs, mics, instruments etc.
 

Beat me to it. Amp sims are for recording, not for sounding like the real thing in your studio through your monitors. You wouldn't listen to Rory Gallagher through speakers and think "That doesn't sound like the real deal. Perhaps I need to hook my CD player to my amp cab" - lol!

For me a big factor in all of this is how the guitar feels and sounds while being recorded, and that typically happens through monitors.  The less the amp sim + chain helps you to play the part the way you want, the less the performance.  Regardless of what it sounds on playback after all is said and done.   At least that's always been my take on it.  
 

Steve has a good point.
The tone/response affect how (and what) you play.

I think where most people get confused is they know how a guitar speaker cab sitting next to them should sound. That is not the way to HEAR the amp sim. When you hear a guitar track on a recording, CD, tape, etc., does it sound like the guitar cab sitting in your living room? Everyone together, NOOO!
It is sitting inside a mix of 32, 64, 512 tracks of other instruments. The sound has been massaged tone and volume- wise to sit in that mix and be heard. I bet that if you could sit in the mix room and hear that song with the guitar track soloed you would be shocked at how crappy it sounds on it's own. And it doesn't sound anywhere close to that half stack in your bedroom. These sims are produced mainly to help you get a great and fast sound for studio monitoring.
Fellow players picked at me about running direct in the PA at first. The typical "That don't sound like no amp" stuff. I got to where I would answer them by walking out front of the PA and saying "NOPE, It sounds like a fully tweaked amp with a world class mic on it without the hassle!"

stevec
 
For me a big factor in all of this is how the guitar feels and sounds while being recorded, and that typically happens through monitors.  The less the amp sim + chain helps you to play the part the way you want, the less the performance.  Regardless of what it sounds on playback after all is said and done.   At least that's always been my take on it.  
 

Ditto. 
 
Furthermore,  amp sims only offer a representation of the real thing. Depending on the case, it can work wonderfully. Or not at all. Smoke and mirror don't always work.
 
A typical scenario where it practically never works for me is when the arrangement is absolutely sparse and the guitar is the center of attention. Say a slow blues, à la Led Zeppelin, with a smooth, mildly overdriven tone and nothing but that guitar in the spotlight.
 
Typically, that's where amp sims fail me, because they just aren't pushing the sound the way a cranked up amp tube does. Something's missing, and it's not a matter of frequencies or distortion type - those can be mimic'ed satisfyingly. It's a matter of behaviour, of gain, of intensity, of density. 
 
In other contexts, they do work, perfectly. All of them.
 
I just finished a song using the Engl model on the POD HD, creating this amazing wall of guitars. Beautiful...

As an engineer, I like the way a real amp mic'ed sounds.  I'd much rather use that, even if I take off a dry line too.