Excellent post. And this is the key:

first work [...] the basic mix and make the 200-400 + 2000-3500 Hz region sound separated and clean and then ask yourself if the mix really need any additional warmth.

Next get a mono compatible anti-phase free stereo placement, then ask the warmth question.

Ditto what pattor said.

Yes one more thing:

All these plugs that claim they emulate tubes or tapes or whatever. What people should understand is that the sound of tubes or tapes is something that comes out from a lot of electric circuits that are working together. The audio is in that gear in an anlogue and electical shape. Those electrical components are in good systems optimized to interact with eachother in ways that digital audio won't ever be able to emulate.

All this "warmifying" should happen before going digital. Trying to add it later is more or less a waste of quality.

I have been using iZotope's Trash. I had to create a few custom presets but I'm finding that I can have great control over the tonal quality of warmth added to tracks or just plan "Balls to the walls" distortation.

I also have Warmifier, Tape Bus & lampthruster but I seem to keep favoring Trash.

If you demo Trash keep in mind that there are NO presets for Tape or Tube Sim's. You will have to create one.

I use the warmifier to add harmonics. I use it instead of an exciter. I think I paid 50 bucks for it. It was money well spent. It does what it does very musically which Voxengo plugs all do very well. The vintage warmer is much more extensive isn't it? I tried the demo last year and liked it but as of yet haven't felt the need for it.

One thing I don't like about Vintage Warmer is that it always outputs in stereo. Often I use it on a bass guitar, and it freezes to stereo. Who needs a stereo bass? I have complained to PSP but they don't really seem to care.

The actual sound is very good.

Don't know what happens on Voxengo, as far as stereo.

Kooz,
I've tried a lot of stuff to get an "analog tape" sound: Ozone, Vintage Warmer, Warmifier, Lampthruster, PSP tape modeler and running out through an actual tube and then redigitizing again. The best thing I've found so far to emulate the "hit" of analog tape is Voxengo's Analog Tape Bus plug-in. It's really good. You can run it with "tape" function switched off which is what I do and then you're basically fooling around with the emphasis and the record level parameters. You can get a very clear sound, but it has the impact of tape. It doesn't explicitly distort unless you use the tape modeler section which I find usually reduces clarity too much. For explicit distortion that has pleasant breakup characteristics, I would use Vintage Warmer, Warmifier, or maybe Cakewalk's tape emulation plug-in.
Mark

Curious.  Can Voxengo's free tube amp be used to do the same job as warmifier?