UPDATE:
Played my MV25 at rehearsal again last night. Cabs were 1x12 widebody closed back ported and 1x12 Electradyne cab. Both cabs on the floor, though I put the closed back on its side so it was taller than wide. I used two so I could put one on the other side of the stage and avoid some of the beaming, though the ported speaker is not super-directional. Next time I will try with just one cab.
Tons of low-end, I wound up turning the Presence up a bit to about 11-12:00. Still some work to be done on tone. It was also very dependent on volume and the guitar I used (I played 3 last night, a tele, a superstrat and a superstrat 7-string). My favorites were the tele on the clean channel (really great-sounding) and the 7 (with Crunch Lab pickup) on lead channel.
I moved the Presence around from song to song, and found that it works well as a master tone control, so I can leave the EQ and GEQ alone, but quickly change the character. In particular I wanted to be able to go from loose and bassy to full and warm to tight and crunchy, and it did the job. It seems a lot like the ISF knob on my Blackstar, though with not as much rumble.
I am ever-more happy with the 2C+ mode, and struggling with the IV mode, as it is not as punchy. I want to like IV mode for the bass boost, but hey, as long as there is a mode I like, great. Also, when my tastes invariably change, I have more modes. I will have to try playing with Presence on the IV mode and see what happens.
At the moment for flexibility I am running the gain at 12:00 and using an OD808 for more drive and presence, plus a BBPre for more soupy leads. I really should run the gain lower, but that would mean using the gain pedals more and not really using the amp tone.
I'm also getting a very nice crunch with the OD808 on the clean channel. I have the clean channel set up similarly to the FAT Sparkling Clean video, and it really does sparkle with my tele. Add the 808 and it is pretty close to how I would set the Crunch mode.
All in all it is a very different beast loud vs. home volume. It had more than enough volume for an acoustic drum set and our vocalist complained that we needed to turn down. It doesn't have the punch of 6L6 or EL34 (obviously) so I noticed that while it cut through on leads I tended to get lost in the mix with crunch chords, they mush out a bit. Turning up the presence fixes that, but at the expense of low-end.