I've actually owned a POD HD Pro and I can assure you that Amplitube blows that piece of junk away (and I even prefer it over the Axe FX-II XL+) but you have to approach the program as if you were actually in the studio micing up a real cab. It's going to take a little tweaking but as a POD user you should be extremely used to that and it won't take nearly as long.
I'm not sure what version of the program you have, I have max which includes pretty much everything you'll ever need for metal but you can demo anything you want for a few days in the custom shop application. If you follow these steps then you'll have the tone you're looking for:
1) Get a DI Box, if you don't already have one, and make sure it has it's own transformer. A Countryman Type 85 or a Radial J48/D2 will work great. Hi-Z inputs generally suck on every interface including interfaces like Apollos that cost almost a grand. The same typical "change your strings" "set up your guitar" stuff always applies.
2) Ensure proper input, the manual states to get the signal as hot as possible you can achieve this in two ways: 1) Crank the gain on the interface until you hit -2 peak picking very hard, depending on your interface and how much you have to crank this could add unwanted noise or distortion. 2) Same but get to -12 peak and use a trim (volume adjustment) plugin before amplitube to crank the signal up. You can also use the input adjustment in the plugin itself but every time you change the preset this will change. You want the signal to show "yellow" on the input meter within amplitube and never clip.
3) Record a short simple DI Track that you can loop. It's easier to make fine adjustments while listening than playing. Double track it as well for later comparisons, double tracked guitars sound different than a mono guitar track.
4) Pick an amp, set all settings to 5 except volume and gain. I'm assuming you'll be clean boosting the amp in which case the amplitube "overscream" is a good tubescreamer emulation. You want the gain as low as possible. Too much gain is the #1 killer of tones.
5) Move over to the cab section, pick your cab, pick your mic (I recommend not messing with dual mic configurations as a beginner. The SM57 is the king of guitar mics) put the mic dead center of the speaker right against the grill. While listening to your looped DI track move the microphone away from the center until you find the "sweet spot". Just like in real life this will vary from cab to cab, speaker to speaker. Once you find that spot then experiement moving the mic away from the cab to tighten up the sound. It doesn't take much. As for cab selection I've found the ENGL Pro XXL, Orange PPC4x12, a few of the "Metal" cabs, and the Slash Marshalls to give the best results. If you're after a Mesa cab tone, you're better off using an IR. I've found the Amplitube Mesa to be too scooped and muffled compared to the real cab (which I own).
Repeat 4 and 5 until you find a combination that works for you then fine tune the tone on the amp itself. Avoid over cranking any Treble or Presence controls, if you feel it lacks high end use a high shelf instead or things are going to get brittle fast. Pay close attention to the volume of the microphone in the cab room because if it clips: you just ruined you tone. Just like the input you want to the output to be in the "yellow" most of the time while playing, without ever clipping. Go easy on the included noise gate as well. Typically the slash gate pedal works better than the actual noise gate in the program.
Make sure you're listening over studio monitors or at the very least some high end audiophile headphones like some 650HDs. If you're trying to dial in a tone over $99 walmart headphones then you're going to over compensate, especially on the bass. Listen at a reasonable volume as well
https://en.wikipedia.org/wiki/Fletcher%E2%80%93Munson_curvesFinally add an EQ plugin after amplitube and low pass between 8k-11k and high pass 80-100k again all depending on the cab to tighten up the sound.
EDIT: As a side note, generally user presets don't translate well. You don't play like them or have their gear. I was not impressed by the JST Toneforge stuff or Bias Amp 2 either but you can still get something at least usable out of them especially if you think a POD HD sounds good lol.
