I have a preference for EVM12L Black Label speakers. The EV classic is a bit less tight on the bass but either way, the speaker will handle what you throw at it. Currently I have an oversized Recto 412 with the EV-BL. I can nail Led Zeppelin and ACDC very easily. However, I also have a Mark IV with same speaker in it. With the open back cavity, the EV speaker can still perform as good as a sealed cabinet but yet sound refined enough for blues, jazz and everything that spawned from the roots. Low volume in 10W mode all the way to 90W going full tilt. The EV will slightly tint the tone but not as dramatic as the V30 or MC90. I am seriously considering converting my head to a combo. That way I get the benefit of the open back and still can drive an external speaker enclosure of my choosing and use the combo as a head. I have used another speaker but they are hard to find in the US, Fane AXA Studio 12L. Similar to the EV classic but very neutral in coloration (flat response curve), almost seems to lack the mid hum you get with most speakers. When used on the clean channel, it s dry and airy tone that you would swear you are playing an acoustic vs an electric but on the heavy side it delivers as well. For a while, I did try out a WGS Black Hawk HP100. That is an amazing speaker and sounded the best with the Mark V when compared to the Mark IV that it was housed in. As a single speaker option, I believe the Marks were too much for it as the driver would overheat (the WGS Black Hawk HP100 would be better suited for a 50W amp). The Jensen JET Black Bird would have been a better choice due to the higher power handling capability.
It all depends on you range of genre you are trying to accomplish. Some speakers may not cover the complete range. I feel that the EV does a great job covering the full range of playing styles and is a great match for the Mark Series amps. I would not recommend the EV for the Royal Atlantic, that amp flourishes with the V30 for some reason. I generally play blues and jazz style of music and work my way up to classic rock. Once in a while I will thrash around with Heavy Metal tones but I prefer 60's -80's. If you are into the 50's the Mark V with EV sounds great. It is all subjective anyway. If you are after a more vintage tone, ALNICO driver would be a good option but they are expensive compared to Ceramic drivers.