Bass intonation

I've played with an awful lot of acoustic bassists over the years, and it's true that even good players sometimes have suspect intonation. However, my friend Mary Stribling, who played bluegress for a long while before she played jazz, has, perhaps, the best pitch of anybody I've ever played with...she's dead on, and her timing is impeccable as well. Not sure why, but even though some of the players I've uesd may have more facile jazz chops than her, I'd rather use Mary cause I really like having the pitch so accurate...it frees me up to concentrate on just the music....HHH
microstick.net PS...and because she's a great bluegrass player, her Brazilian playing is great, too, cause both hit the root and 5th on 1 and 3...