I would say they're hit and miss. I've found that they can get a lot of stuff right, but I've noticed in Jammit's tab of Holy Wars, they've got the fingering for Dave Mustaine's last big epic solo completely off. They have the chromatically ascending part building up to the end of the solo tabbed out as a sort of repeated three-string mini sweep instead of being played on the just the G and the B string like how Dave Mustaine plays it.
Also, they don't have John Myung's ascending bass run in the pre-chorus to Pull Me Under tabbed right. The sounds are right, but on the tab in Jammit it looks like it's moving to the G string, and then in the next measure it moves all the way to the 9th fret for the next flurry of notes. Very, very impractical. And most importantly, not the way Myung plays it. He plays where Petrucci plays on the neck in that part.
So to answer your question, they have all of the sounds of the notes transcribed right, but in some cases they aren't tabbed out in the correct fingering.
My best suggestion for you is to use Jammit as a reference. Jammit has a good idea of the getting all of the sounds right, and sometimes they get the solos right, and a lot of the times they tab out stuff you wouldn't have even picked up with you ear because of the isolated tracks. But do not use it as the end all be all of the transcription in regards to guitar and bass. The official tab books are probably the best bet for that, as they are transcribed by very accurate transcribers and have even had John Petrucci verify it himself in regards to the Black Clouds & Silver Linings tab book.
Although a suggestion of mine would be to look at what Petrucci and Myung are doing in live performances for the most accurate representation of how the music is played.
Hope this helps!
Topic: Are the tabs accurate in Jammit? (Read 2907 times)