I see the OP has made their purchase, but for other readers I'll throw in. I own both the Fishman Loudbox Mini Charge (has internal lead acid rechargeable battery) and the Roland AC-33.

I like them both. If I was doing it over again I might have just gone with the Roland because it is adequate for my needs. However, the Fishman is louder, especially going battery powered. The Fishman delivers it's full power using it's very heavy internal battery. However, the Roland's power is SIGNIFICANTLY reduced when going battery. That is according to manufacturer spec and it is a noticeable difference. So if you really need a battery powered amp, make sure you are considering the Roland based on it's reduced power without the AC adapter.

My first amp was the smaller Roland Cube Street. The smaller one with the slanted front, not the larger one. If I was doing it over, instead of buying the Fishman, i would have kept the Street, and picked up an AC-33. Then if I needed more battery-powered volume I could use the Street for reinforcement. I prefer carrying the AC-33 over the Charge. The AC-33 is a little smaller and is much lighter than the Charge (though the Loudbox Mini without the Charge feature puts it back in the weight range with the AC-33). But I usually take the Fishman Charge anyway because of it's superior clean power and volume.

You may have guessed by now that I am not a professional performer, and you would be correct. I lead local uke gatherings, a sort of uke club, in Austin TX. I use the amps mainly to play music that we play along with. They both sound great with amplified recorded music, not distorted nor bass-heavy, just what we called High-Fidelity when I was a young man, before everyone wanted the bass amplified to a ridiculous level. I have tested them with just ukes going through them, with some very nice ukes with pro-quality pickups and I thought they both sounded very good.

I have tried connecting the two for a lower volume from each amp but the same overall ambient sound. However, every way I have tried I get a slight hum or buzz. I have used high quality cables. I assume there is a way to do it without the buzz but I haven't found it yet. I don't know if it is easier to daisy-chain same brand-name amps, or if it is generally not done. I'll try to report back if I find a way that works.