4 JP rifles since 1997 and still have all of them. They work AND are more accurate than just about anything out there for the uncompromising reliability you get.
ANY rifle will jam/puke if not properly maintained. JP's have a knack though for keepin' on runnin' if you just feed it some more oil.
As for accuracy, 0.17" groups are near impossible to beat on an AR platform. I guarantee you nothing at Bushmaster can meet that.
As for distance, a 16" rifle will drill out to 600 yards all day. You lose a little (and we're talking less than 300 fps) with a 16" vs. 20"...probably a lot less. I'm ordering a new CTR-02 when I get back from Afghaniland with JP's new 16" barrel. It'll fit in nice with the 20", 2-18" and re-barreled 16" JP that I have.
Buy with confidence. Oh, and if you need some real world qualifications, the Viking Tactics line of JP rifles designed and spec'ed by Kyle Lamb, have more than enough credentials.
Rich