Howdy. I've owned an HD500 since 2010, kept up with all firmware updates, and skimmed threads regularly. Here is a small list of frustrations I've had and still have with the unit (suggestions welcome - especially if I've forgotten fixes in previous updates):

1. Non-tweakable power-amp crossover distortion modeling.

Line 6 apparently modeled the way EL84s get fizzy when you crank the master volume, set every power amp model to 10, then released the unit without a master volume control. After alienating countless players, they rectified this huge mistake with a firmware update that included tweakable power amp parameters. The first thing I did was turn the modeled "Hum" to 0 on all my patches, then adjust the resonance and thump to cut out the unnecessary woofiness that, while a nice way to show off the individual modeling, can overdrive the inputs of whatever you're running the POD into. This also contributes to

2. Goofy volume differences among the modeled amps (in the name of "accuracy"), but no global volume settings to compensate for said differences in modeled volumes of the amps.

A control for the percent of modeled crossover distortion is BADLY needed. The tone of the /13 amp model is one of my favorites, but I personally find it unuseable due to the modeled crossover distortion. I understand that one can compensate (to an extent) with the master volume, mic, and cabinet resonance controls; but it's an unnecessary amount of extra work. Note that the modeled Class-A amplifiers shouldn't be exhibiting crossover distortion (and the "Bias" control being turned to Class-A should remove this from the AB-models); so this may be a partially or entirely-separate issue. Considering that the "tweaked-by-Line-6" models consist of mixed preamps and poweramps, I'm assuming the vaccuum tubes are hard-modeled to their respective preamp and power-amp models, and therefore the behavior of the tubes (desireable and undesireable alike) are non-adjustable. This ends up being a dealbreaker for many of the models. For example, I can overdrive the preamp input on several of the Fender amp models and achieve the fabled "fizz" simply by plugging a humbucker-equipped guitar into the Pod HD. The Pad switch is supposed to be the fix for this, but is a poor workaround that assumes not only the willingness of the user to readjust levels in the rest of the signal chain, but to avoid using different guitars with differing output levels. This is no more acceptable than if you found out you can only use the middle pickup of a strat with the PODHD, because the frequency spikes of the neck and bridge pickups will result in digital distortion that cannot be tamed. Even though that scenario is thankfully not the case, there is an unfortunate inability to tame frequency spikes. This is complaint #3:

3. No (clear) EQ band selection above 2.2 kHz = Untamed high frequencies.

"Just turn down the treble and presence", you might say. Well, if the modeled amp's treble band is 1.2 kHz and the presence is 7 kHz, then by turning them all the way off, you've only elected not to boost frequencies at 1.2 and 7 kHz. But suppose you want to cut them - You can use an EQ block to notch that treble frequency, but the EQ band selection ends at 2.2 kHz with the Graphic EQ model. You don't get a Hz-kHz band representation on the other EQs, so you use the low-pass filter on the mid-focus EQ or the only recently-added "Vintage Pre" model, but realize that, rather than notch out the frequency you want, you're cutting everything above 5 kHz - Throwing the baby out with the bathwater. So you try to compensate by turning up the amp model's presence control, only to realize that really you only want to cut the frequencies between 3 and 5 kHz, and boosting frequencies at 7 or 10 kHz (depending on the mapped band of the amp model's presence control) is just moving things even further in the wrong direction. The only thing left you can think to do is plug your old Danelectro Fish-n-Chips EQ pedal into the POD FX loop, which sucks your tone and only leads you to settle for a tone that bugs you.

4. Looper has bells and whistles, but no quantizing. :facepalm:

I can play my out-of-synch loop both backwards AND at 2x normal speed! You tell me that it's really more of a bonus toy than a "serious" or "dedicated" looper, and that I should just buy a dedicated looper if that's what I need. I agree - So how about not including a looper that's outclassed by the obsolete Digitech GetNex loopers from 2003, and instead making that extra DSP available for use in the rest of the unit - Lord knows the HD500 needs i-DSP LIMIT REACHED.

5. At the end of the day, the unit is a POD X3 Live with much higher DSP demands that it can't meet.

Apologies if it turns out that was debunked, but I remember that being "common knowledge" two years ago. The Preamp-Only models are the workaround for it, but it's still a step-backward from the last generation of PODS that allowed you two amp and fx-chains per patch. I predict this being a bit of New Coke/Coke Classic marketing for when Line6 comes out with the next pod that finally has the processing power and memory to meet the demands of the current modeling algorithms.

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Sorry if any of my post comes off as snotty - The PODHD has been an indespensible part of my rig since I bought it, and is still leaps-and-bounds ahead of Digitech's RP1000. It's just that these problems have been dealbreakers for many players, and I can see why. But these restrictions have also led many users here to come up with creative workarounds that allow us to emulate more-complicated routing/rigs (such as pitch-modulated, hard-panned stereo delay with pad-like filter effects).

So, any suggestions for workarounds or fixes to these problems?