Triode or Ultra-linear? Why?

The only tube amps I've gotten along with have been pentode/UL. SE, yet to hear a PP. As you likely can guess I mostly listen to metal, classical, and electronic music. Frequency extremes are important.

I agree on dedicated amps without switches, I like purpose built equipment. Too many options seem to me like a lack of direction from the manufacturer. There are plenty of SET fans out there, I don't see them missing the switch. And it's kinda neat to see what you can pull off with really low power amps, I'd be tempted if it wasn't for the mid-range focus of much of these amps

I had a VAC amp that was switchable from ultra linear to triode and always preferred ultra.  Triode was too soft and lacked dynamics even with my ESP speakers which present a tube friendly load.  Now I have a BAT amp which is only triode and lacks nothing in drive.  I don't believe the switch option provides a fair comparison.  Pure triode sounds awesome at the expense of inefficiency and massive heat. 

I find my lofi tubed system absolutely needs the UL/triode option. The majority of my listening is records, many are simply too "hot" when cranked 
ocaissionally in UL. Hearing a Les Paul or cymbals at near concert levels isn't the same when I heard the same song 40 years ago.

UL for me is also a "loudness" switch when listening at low volumes.

I suppose  actual system configuration also,determines what you like.

Presently listening to SD "Katy Lied" in triode. Sounds pretty good for an album they hated for its SQ.

After decades of tube and SS stuff I'm way into a Dennis Had single ended pentode amp now ("Fire Bottle" HO, ranted about by me frequently…sorry... ), and although you should use it with relatively efficient speakers to enjoy all the 12 watts each side offers, I doubt I will ever go back to anything else…as with any great amp (used properly) it doesn't care if it's called on to pump out Steely Dan (I still have all my 70s vinyl), or Benjamin Britton or acoustic jazz…everything works, and surprisingly at all the loudness I seem to need…a great low volume sound also, and other than turning my 2 REL subs up or down here and there I have no tone controls (my DAC has filter options, but that's it). Katy Lied indeed, and I like it.

Also, I think tube guitar amp companies should all consider making a little stereo amp…that Mesa Baron was so cool, and if you can buy a USA (Kentucky) hand made tube rectified single ended class A tube (EL84s) amp head like my 18 watt Burris Royal Bluesman (it's royal blue…get it?), which includes a preamp section and spring reverb for around a grand new, these guys are missing the audio geek boat, so to speak.