Taken as a whole Belichick's, overall record is impressive, but when you look at the one variable, (TB12) that has impacted his record, it's a little less impressive.
With TB12: 249-75 (.769)
Without TB12, incl. Cleve.: 83-104 (.449)
Impossible to say how he would have fared in NE if they had not drafted TB12 in the 7th round, but one thing is for sure, he would not have had the success he has had.
Great coach or great QB?