You're right that people out front will generally not notice what we're using or whether the bass sounds better or worse. As long as it's solid and full and provides a decent foundation for the music, that's the important thing. Everything else is for our benefit.
I've also found that Markbass gear sounds OK - not bad, but not great - on stage, but projects very well and sounds good in the room. I guess it's really only we bass players who worry about the tone of our kit. That's good, in that you will play better if you're happy with the sound you're getting, but apart from that, it's probably not worth obsessing over it. Of course, I've been through a number of set-ups to find something I like (as have we all), but if I'm honest, I'm probably the only person who is bothered about it.