I have been please with my MIM Jazz as well. I'm having a few mods done right now, but I think they are good, solid basses. Head and shoulders above my Indonesian-built Squier.
"Nothing is what is seems, but everything is exactly what it is." B. Banzai
When I purchased my MIM Jazz, it was used and came with flats. I need a punchy sound, sound flats never did it for me. Instead of changing strings, I purchased other basses. I really should try mine with rounds.