Most of the guys that I try to emulate sit up on the beat. The problem is hearing the time and dance of the groove so that you don't rush. It also depends on the relationship with the drummer. I used to practice with the metronome set to 2 and 4 and try to feel beat placement while being aware of the tempo so that I didn't rush. I'd liken it to having a rubber band between the beat center and me and keep that tension consistent. That way you don't rush. With different drummers and in different situations the distance between your attack and the beat center can vary, but the awareness of that tension---and not increasing it is the goal. If the tension increases you rush. I'm being overly analitical about this and ultimately it is counterproductive to TRY to think this way on a gig. As a matter of fact, any time you think about beat placement on a gig will insure that it will feel like crap. It has to be internalized. Hence, breaking it down and learning to practice it. When I started out, I used to rush like a mofo. So I had to figure out how to practice to have the time and relationship to the beat internalized. Then you have to deal with the drummer. You have to feel the drummer's DANCE. I use this term because it's not just a matter of high hat, ride cymbal, etc. It's all of that combined that produce his groove. I tell students that they have to hear the drummer's dance and naturally place themselves as part of that dance. I know so many bassists that can only play with a certain kind of drummer. Obviously, with a drummer that drags there isn't much you can do but get through the gig and get paid, but it's nice to be able to play with drummers with different time feels. Lots of guys can't play with "center of the beat" drummers. These bassists can only play with an "on top" drummer. Things feel like crap because the bassist's beat placement is so far ahead of the drummer that the beat is uncomfortably wide. And it will have a tendency to rush because the bassist is trying to pull the drummer to his perceived beat placement.
So, my advice is ---practice feeling the beat in different ways with the metronome to solidify yout internal time. Listen to a lot of different bass/drummer combinations to hear/feel what they are doing. If you listen to a lot of successful bass/drummer combinations these will also be internalized as feel references. Listen to how the drummers you are playing with feel the groove. This will also become a natural tendency that will be internalized.
If you do all of these then you can do the most important thing----forget about all of this crap and play. You really can't groove if you're in your left brain analyzing. To paraphrase Miles---if you're thinking about the moment it's already gone.