Hey, Dave!
Definitely have gotten yourself into one of the big topics amongst guitarists, here. It's a great topic of discussion and firstly you have to know that everything in music and art boils down to personal taste. Modeling amps are great, please don't take my recommendation to get a real tube amp as a knock on them entirely. I'll try to explain the main differences for you first.
It's important to note that modeling amps, being solid state, run their "tone emulators" through digital circuitry. Now, these technologies have come miles since I last owned a modeling pedal board. I've owned a DigiTech RP80 (I think?), DigiTech GNX2, and a Line6 PODxt Live at different points in my playing career. All of which I put a lot of hours on and all of which I really enjoyed in those phases of my playing. Historically, it's difficult for digital modelers to emulate the saturation of tubes and provide the same dynammics. Dynamics being how they react to each different pick attack. Light, Hard, flat, plucky, etc... The tones of modelers tend to be compressed in this way. Compression can be good, but it can also be bad. You'll probably find that modeling amps are cheaper but there are more expensive options out there. Obviously these more expensive options are going to more accurately replicate the amps and pedals that they're representing. So, modeling amps are good for what they are, they're just never going to be what they're emulating. That's a good distinction. If you're starting out and want to mess with the multitude of pedal and amp combinations, then this is most definitely the way to go. I used my gradually upgrades in modeing pedal boards as a way to learn how different elements of pedals work. How effects work together, compressors, delays, cabs, amp heads... Going through all that I was able to know exactly what I wanted later. So, this is a good place to start as any.
Now, about pedals. Since most every pedal in these emulators are digital reproductions of an analog circuit, they're only going to get so close. I will tell you that there is still no subsitute for the real thing. Like you said, the lexicon of tone terms is big and varies slightly, but the best way is to actually HEAR what these pedals sound like in real life. Going to a store (not likely able to do now...) and playing gear is the best way to really let your ears decide. Otherwise you might never know how good something can sound. The funny thing about pedals is that even the same type of pedal can sound entirely different depending on different things... being analog, the tones may change slightly on pedals from even the same manufacturing run. It's funny that you mentioned Big Muff's... I have a late 90's Russian Muff (Black, not green) and it sounds great. I recently purchased a reproduction of the Triangle Big Muff to replace it on my pedal board and this new pedal sounds incredibly more articulate than my Russian Muff did.
The terms that are sometimes hard to get used to. What I mean for Vox chime is that there is a harmonic chime to the tone that favors the treble side while not allowing the whole tone of the amp to be too brittle. Fender's cleans are known for being transparent and allowing the guitar and the player to really dictate the tone. Vox amps have a bit of color to them and add a bit of dirt along the way. Another term that people don't really understand is "headroom". This is usually used to describe the tonal dynamics of an amp or tone. This can be where you can play very lightly and the volume reflects that... then when you gradually play harder the volume and dynamics are reflected in the playing. When you start to apply compression to a tone, these dynamics get scrunched together and you will notice that no matter how hard you play or how soft you play, the tone comes out within a smaller range of volume. This compression is what happens a lot with modeling amps. It robs the natural headroom from the tube amps that it's trying to recreate. That's the main argument against modeling amplifiers, anyway,. The character of the tone is very difficult to model, which is why there really aren't any modeling amps out there short of the Kemper that would satisfy anyone that does play real tube amps. But, that's not the purpose of most modelers. They're a tool and they're a great tool. So, again - Go for it if you're on a budget. They give a great amount of fun things to explore your own tastes!
Someone mentioned the Anderton's Music videos and I can second that. They do a great job! They even have a video where they put the Kemper modeling amp against the real deal and they have a hard time telling which is which. Obviously, the Kemper is on the super high end of technology and price... But it's fun to see regardless.
Anyway, great discussion here! If you have any other questions or wonderings, let me know! I'm happy to give my insight on tone that I've learned from my 20+ years of tone searching.
