Had Slax and a 2017 BE100. Love both, but I'm a fanboi. DNA is similar for both, but they can be different enough, especially the clean channels and gain. From memory, Slax has thicker, meatier and hairier gain. It always has the Sat switch on, so if you have a BE, flip the Sat on and it will get you somewhat close to Slax, but Slax has an angrier gain and more of it.
I personally love a Thump/Resonance knob on any amp, so for me, that's something missing for me on the BE100 that I loved on the Slax. I don't really play clean, I use my volume knob for that, so I never used the Clean channels on either. Clean on the Slax is pretty cool; it's a dirty clean and can do some great classic rock. I mainly used Channel two on the Slax; Channel 3 I used for lead tones. On the BE100, man, I really loved that amp. Pure rawk tones and can get really chuggy with HBE and then some with HBE and Sat switch. I tended to use the BE and HBE channels and if I wanted super metal, I would
If you wanted, for the BE100 stick an EQ pedal in the loop to add that "thump" knob capability and just get a good boost to take BE or HBE into gain Slax territory. It still won't be exactly the same, but it could get you kinda close. Dave can tell you better.
Or, get the BE100 DLX. I played that one for an hour and LOVED it. It can get closer to the Slax and do a whole lot more. It's a dream amp for me.
Cheers!