I own an EVH 100w EL34 and I've played a Badlander 100 in a music store. I can't directly compare them but from what I could hear, the EVH is slightly more articulate, while the Badlander has a slightly fatter kind of tone but still more low end filtered than a standard Recto.
To me, the biggest differences in the amps would be how their negative feedback networks work in conjunction with the preamps. The amps actually sound fairly similar, both having high gain preamps with built-in low end filtering and EL34 power sections. However, the best way to think about the biggest differences between them is like this:
The EVH has standard Presence and Depth controls that dial in the respective amount of negative feedback in the high and low frequencies. The Badlander's poweramp "Presence" and "Depth" circuits are locked internally on 10, with a knob labeled "Presence" that is actually a hi cut at the end of the preamp. Additionally, the EVH probably has very slightly more aggressive low end filtering going into the preamp. This additional low end cut makes the EVH tone "more honky" or "clearer and more articulate" than the Badlander, depending entirely on your guitar, pickups, cab, and amp settings. Whatever differences you can imagine between these two types of systems is basically the difference between these two amps.
Here's an Ola video where he shoots them out with different cabs. Everything is time stamped so you should be able to jump around to just the Badlander and EVH parts.
It’s like they took everything I like about the “recto” tone and removed it