Based on your posts I have read, moving on seems like a good idea to me...Line 6 culture and the HD/DT system doesn't seem to reach your expectations and is causing you frustration....Nothing wrong with moving on..Finding the gear that fits your wants is the important thing...good luck sir..

I've had my DT25 and extended cabinet for about a month now. I like it. I do plan on replacing the speakers and modifying the bottom cabinet to be like the top cabinet. Ported on the back and close off the front ports. I also plan on a second stack for stereo, more power and redundancy.  New tubes as well.

I do get a little tired of messing with the HD500 and the amp together but without the POD connected to it, the amp only has two channels and that's not enough.

There is no perfect amp but this setup is pretty nice!

"1) Failure to publish a list of USB to MIDI interfaces that work - in presale information: At the vrey least, give this information to dealers, because anyone who is going to buy a DT25 is going to want the option of using the new firmware, and should not be sent on a wild goose chase.To not share the information they have readily available is just obnoxious."

Even if they give the info to the dealers, the dealers seldom read it. In this case MIDI is a standard communication protocol from the 1980's and they cannot predict what device your computer will work with. I have used M-audio, Roland, and an old controller from the 1980's with my DT25 without issue. The device speaks MIDI. If you are having problems implementing a MIDI port on your machine that is between you and the MIDI port vendor.

"2) No useful documentation: The V2 release is essentially undocumented. I had to go through tech support to find out what the knobs on five models (9/15, AC15, AC30, Supro, Flip Top) do once the V2 firmware is installed. Someone here pointed out it is in the HD500 advanced user's guide. Great. And that does a DT25 buyer what good until he/she is told? The Amp Gallery is nothing but marketing copy. I know what a Hiwatt is. Tell me how your amp works."

I agree, my old flextone documentation had the type of info you are looking for. This level of detail seemed to cease about 4 years ago with Line 6. They did do a good write up on the MIDI implementation.

"3) Drive knob: Seemed to be nothing but a redundant volume on the Twin and Hiwatt models, for instance, but I couldn't be sure. The answer I got is that what it does depends on the amp chosen. That's the first sentence of what is probably a two paragraph proper answer, plus a chart of the 30 amp models, showing what it actually does with each."

Again I agree, docs are all sizzle and no bacon. The user community is very helpful though.

"4) Extreme volume level mismatches: This wouldn't be a huge problem in and of itself, but it is a bit of an annoyance to be experimenting, and then suddenly it's WAY LOUDER because I went from the Hiwatt to the AC15 (which is also pretty counter-intuitive). I get this is a limitation of the hardware design. I could probably work with it. But when I'm guessing at so much else and already have a sense that Line 6 couldn't care less, it becomes a sticking point. Brains are funny that way."

This could have been implemented better or at least explained better. The issue with modeling into a tube power amp is that in order to get the power amp to react in the the desired manner it needs to be pushed or not pushed at an appropriate level by the pre-amp. This is more an issue of melding modeled pre to real power amp topology. Since they have only 4 amp topologies and 30 models there is going to be a compromise. My perspective is that the amp was designed to be able to switch from A to B on the fly with the WYSIWYG knobs and you can adjust the volume to be consistant between the two. Live switching amp models on just one of the channels would introduce your issue, but you would have to adjust the other knobs as well. I'm glad they did not sacrifice modeling accuracy in lew of volume concerns.

"5) Functional use of V2: It's insane that we have to either use an iOS app (which makes no sense on about 5 levels) to get the benefits of V2, or be saved by a volunteer's (excellent) code. LIne 6 should be offering to license that program and make it available via their website. People who bought this amp and aren't HD500 users are not likely to be command line MIDI programmers."

They could have been more inclusive, but hey did not remove function from when I bought mine a year ago. They just added function for those that wanted to buy or had bought the iOS device. The assumption that people who bought this amp aren't HD500 users is not true in all cases. It does sound like you would prefer the presetting of a POD HD unit. The amp alone is just a two channel amp with a lot of options. It was designed to compete with the Egnator Tweaker and the Mesa Trans Atlantic that contain no presetting and no MIDI implementation. The intension was not to create a new Vetta or Flextone that had full POD's integrated with them. They wanted to create a dumber amp that could be attached to a HD500 if you needed the presetting and effects.

I think mine goes back to Thomann. Its a pretty nice amp, but i also have Axe Fx II and i like it better.