As long as we aren't going to have a shoot-out, how about a comparison to things we already have information about. Here's my take on the new 360m vs. the original 360 vs. a 320 head and 408 cabinet.
Loud? Beats me what any of 'em will do. I have never had to turn any of them up much.
Controls. The original 360 had one volume control knob. Turn it up, it got louder. The power amp was running wide open all the time, since there wasn't even an on/off switch on the 361 cabinet. For tone control, there were five (if I remember right) presets for eq profile, a bass pot and a treble pot. Those simple controls were far more versatile than they should have been. The fuzz circuit on my 360 doesn't work very well, and the electronic tuning fork is something that a cheap tuner surpasses, so I don't use either of them. There is a single channel. The 320 has two channels, a five band eq, bright switches and tone pots on each circuit, and the ability to use both circuits with the eq and tone controls set differently for those channels. It's a little complex, but it is a whole lot of fun once you figure out what all that stuff does. The new 360 preamp is more like the original 360 than the 320 head. The variamp control lets you select a frequency range and then either boost or cut that range. It has tone pots, a "growl" circuit, and a compressor. The big change from the original 360 is that it has a preamp gain and main volume control. The power amp is in the cabinet, but the cabinet now has an on/off switch. There's also a high frequency horn that is switchable.
Cabinet. The original 361 is a w-bin with a single 18. The 408 is a behemouth with four 15s. Two fire at each other in a center slot. The new 361m that I own is a w-bin with a 15. There's also a new 361 with an 18, but the original 360 and the 320/408 were both absolutely overkill, so I figured a new big one would be overkill, too. For most purposes, the new smaller one is overkill, too, but I wanted it and had the money. The big one only costs about $100 more, so if you like overkill, that's the way to go.
Weight. Both old and new 360 preamp heads weigh nothing much. All the weight is in the bottom of the speaker cabinet, which has wheels. The 320 head is a beast. I find the 408 cabinet to be bulky, but fairly easy to move around. Loading any of them into a van is straight forward once you figure out the technique of sliding it in on its back. Both old and new 361s have a wood bar across the front of the cabinet bottom, which makes a fantastic handle for levering them into a vehicle. Stairs are a bear no matter which one you are dealing with. Best to have a roadie if you have to haul any of these up more than a flight of stairs.
Sound. That's subjective, so this is my take. The original has a rich, full sound. It could almost be described as a juicy sound, altough that's not right, since it isn't muddy or soft. I have never managed to make it sound harsh and scratchy like a whole lot of other amps. An Acoustic 370 comes to mind for the scratchier sound that I don't like so much. The 320/408 can sound very much like an original 360, but it can do other things because it has more controls. I think it sounds a little more mechanical than the original 360. I can't tell you what that means, since I don't really have words to describe sound accurately. If you think of the original 360 as a blue-purple sound, then the 320/408 has more red and yellow in it. It's not quite as pure sounding. The new one is dryer sounding than either of the others. It is higher fidelity, meaning that you will hear exactly what you play. Things you could get away with if you were playing through one of the older ones won't slide by through this one. Because it has a high frequency horn, you can get more high mids and overtones. Or you can turn it off and sound almost exactly like an original 360.
I have played shows with all of these and haven't ever had a problem with volume. The old ones never got used with the upright, so I can't say how they would do. The new one makes the upright sound like an upright, only projected all the way to the back of the room. There's a little knob twiddling you have to do to make it work, but that's hardly a surprise. I don't use the growl circuit, since I don't like a distorted sound as well as a clean sound. I don't think it is exactly a fuzz circuit, but then I haven't spent the time to figure out exactly what it does. It boosts volume, so if you want to use it to pop all distorted into the foreground from a clean background role, it would work well for that.
All three of them project. There's not much need for FOH reinforcement. The new 360 preamp has a DI plug in the back. I don't remember whether there's any provision for direct out from the 320, but if there is, it isn't a balanced out. I'm sure there's none on the back of the original. You could use the new 360 as a preamp and di box if you wanted to.
Just so you all know how to interpret my comments, I think the original 360 sounds better than an SVT on a refrigerator, and I have heard them side by side. I can't describe the difference except to say that the SVT has a harsher, flatter sound than the 360. The new 360 has the same full, sweetness if you want it. It also can make what you put in louder, without much coloration. It is a w-bin, so it sounds better in the audience than it does on stage. It is also tolerable to stand in front of at decent volumes, since the sound doesn't seem to really reach full strength until somewhere pretty far in front of the cabinet. That's a characteristic of well made w-bins, no mattter who made them.
I hope this is useful. One last thing - if we are going to bench race, I can offer this: a rig that includes all of the above, plus a pair of 811/812 PA cabinets powered by an Acoustic 400 power amp (two 370 power sections). Each 812 has four front firing 15s. That should be enough horsepower to dim the lights in the next county and set off earthquake warnings somewhere.