I bought this yesterday from the gentleman known here as @lowregisterhead and I've only tried it briefly before purchase (to confirm it was as epic as the YT videos suggest) and for about half an hour last night (until Mrs Axe complained about the windows rattling). I'm therefore very much in the honeymoon period!
Although there are more knobs than I'm used to dealing with, it didn't take long for me to get familiar with their operation:
Character switch - too much bass boost for this to be useful to me, so I'm unlikely to be using this function. There is plenty of range on the Gain control. The Comp/Limit feature goes from just limiting peaks, right up to a pronounced sustain.
My gigging amps have tended to have valve preamps with passive tone stacks, so the active Filter section is a bit of a departure for me. I quite often need to cut bass when using my BF Super Twin, but (at least in my living room) this control sounds right at about noon. I boosted some Mids at 200Hz for my favoured sweet spot. The Treble control is really effective in bringing out the clank of a Precision. At first I thought it might be adding noise, but I discovered this was coming from the bass (with hands off strings) rather than the amp. The Bright control doesn't do much for me. It is focused on 10kHz, whereas the Super Twin doesn't reproduce much above 4kHz, plus I use flats. It might be different with roundwounds. The facility to make quick comparisons between flat and EQ'd sounds using the Filter switch is handy.
The Comp/Limit circuit comes after the Filter section, so with some Comp engaged, boosting the Bass can change the tonal balance without massively changing the volume, and still lets the fundamentals come through when playing up the dusty end. I set it so that it controls the transients on the one song where I (reluctantly) have to slap (Ashes to Ashes), evens out the harder attack when picking with a plectrum, but otherwise leaves my signal alone. I like it.
Drive is great for adding in some 'fur', in fact at settings below noon it is not a million miles from how my Ampeg PF-50T (sold to fund this purchase) used to sound when pushed. I see it is switchable, but it does bring in a significant volume boost, so I don't know how useful that would be in a live context. I might investigate foot-switching, but I'll probably just set and forget - I am not a mid-gig amp-knob-twiddler. (If anyone knows what goes on in the RM-4 footswitch, please let me know - I expect there is just an LED and current-limiting resistor on each switch.)
As I understand it, this model has the filters from the HD350 (which people seem to prefer) with the extra features of the HD360 (e.g. light-up push-switches). Although it's possible to pick up an HD350 for quite a bit less, I much prefer the look of this version's front panel, and it has a strong 'Rolls Royce' feel about it. The amp really brought out the difference between the basses I played through it, rand somehow seemed to increase the range of their passive tone controls. This may seem like an odd thing to say, but the thing I liked best about the TC Classic 450 I once owned was the ability to dial in some subtle compression and drive for a vintage-y sound, and then leave it. This amp does that too, but in a much classier package. It has also save me having to put together a pedalboard.
Roll on the first post-lockdown band rehearsal.
You're going to want pics, so here are a couple of photos from Dave's ad: