Hi G-Dog and cheers for the addition into the Rumble Club - what an honour!
Indeed the red lights do work - bit of a gimmick but I quite like them, and even if you don't you can just disable them.
I live on a lovely small island called Guernsey, which sits not too far off north-west France. Unfortunately, the penalty for living in a small & beautiful island is lack of availability... And bass amps aren't an exception!!
I'd have to travel off island to actually try out the rumble 500/800 so I have to purchase somewhat blind. It's times like these that the internet is a blessing!
As for tone, I'm not much of a tweaker and I wouldn't consider myself too fussy, although I do tend to like the mids to pop somewhat and not have the sound too 'muddy'. Both the 500 & 800 fit the bill I think, it's just whether the extra ~£80 or so on the 800 is worth it. I could easily be carried away with the benefits but need to set a ceiling
I never actually picked up a bass until a few years ago. I was asked to join a band as they assumed I played bass, which I didn't (I'm primarily a drummer) however I had an old Yamaha (I think TRBX174) passive that my aunt gave to me years ago so I self taught, we had a practice and they were happy and the rest is history!
Seasoned bass players often recognise my 'poor' technique however, I mostly play with my thumb which can be limiting and it's calloused horrifically!! I need to learn proper finger technique someday