Can't really go wrong with Genzler. Whatever you do get something that won't leave you feeling lacking in the volume or frequency departments. I think that's likely to be where most people wind up making mistakes and needing to start over.
Bass players (myself included) I think get a little too precious about our amps. When you play anything other than the smallest venue, we wind up going direct to the board anyhow. Genzler is a great choice because it represents really strong value, $800-900 new for an MG800, or maybe 500-600 used, is a great deal. The cabs are a touch more expensive but still really nice. Genzler is a very neutral sounding amp. Ampeg, Mesa, GK, etc. all have much more identifiable sonic signatures, IMO. You can play hard rock with Genzler, but it might not be my first choice, just like you could play jazz with an ampeg, but it might not be my first choice either. Genzler does the round, hi-fi-ish sound perfectly, and that's a very versatile sound. But at the end of the day, bass is not as harmonically rich as guitar based on the frequency range involved. The difference between a fender and a marshall amp are much bigger than the difference between a genzler and a bergantino, for example. And those differences show up when you put a mic in front of them, in a way the audience will not experience when running through a direct box. I sure do love plugging into my rig in my home studio and jamming along to my favorite tunes tho, sounds great and great fun!