I may as well chime in here....
I have no experience with the mini versions or the EL84 powered amps offered by Mesa. From what I heard thought the Video and sound samples they all sound great. The RA100 will do what your band plays quite well. As for the clean channel of the RA, you can get some creamy blues vibe, not as bright as I would expect but well balanced. Push the gain on the clean channel and it becomes alive with enough edge and soft clip that is a pleasure to experience. The Hi/Lo also has mojo for that British invasion and classic rock and with some respects Heavy classic Rock. There is also the Roadster too, both clean channels have two distinctive modes TWEED and BRIT that can provide a hot rod fender or early Marshall bite. Depending on what instrument you play, the high gain channels will give you some awesome Marshall killer tone with a single coil guitar like a strat, hook up a humbucker guitar and the amp turns into a beast. What I like about the Roadster, I can get a nice bell like tone in the clean channel for ballads, soulful blues or push the gain and get similar tones and gain characteristic of the RA100. I play a mix of everything, including heavy metal and more modern styles so the Roadster is a perfect match for my use. Actually both RA100 and Roadster are great performing amps that will not let you down on the road or in the studio.
Based on your description of what you are looking for, RA100 will probably be the best fit. If you ever get a chance or if you find both amps for sale, try them both out. I have seen more used Mesa boogie amps for sale though Sam Ash than I have at GC, it is hit or miss unless you find a dealer.