My first(and currently only bass, as i'm going to pick up a rickenbacker at the end of this month) is a 1999 MIM Standard Jazz Bass. Swapped the bridge, feels amazing and sounds great. I'm content. I guess what I'm saying here is that each instrument differs - my thunderbird I recently sold didn't feel good, and could have used a pickup swap. Case by case. But I couldn't agree more with this: Playability/Feel is THE MOSE IMPORTANT!
1) Playability. If it plays like crap I won't play like me.
2) Tone. Easy enough to "fix" in most cases. But these days even some really inexpensive basses sound just fine.
3) Reliability. I gotta be able to know that when I turn the tuners they will both turn and stay in place. Same goes for pots, bridge adjustments, etc.
Other than that I can make whatever work.
