Not necesarily the best coach but the coach that has the best system to fit your team and get the max out of your talent.
For the Sixers i would go with Byron Scott because i have always liked his coaching style. He gets the best out of his players which would be very important considering we are running low on talent. His offensive sceme would work pretty well here because we could be like a lesser version of the Nets teams he took to the Finals. We have a very good distributing PG in Andre Miller, an athletic swingman in Iggy, and athletic big that could fill the Kmart role except obviously with our team Andre would be less of a focal point than Kidd was for them because Iggy is the man and main offensive threat.
His offensive sceme would work pretty well here because we could be like a lesser version of the Nets teams he took to the Finals.
He is awful as an offensive coach, does the same plays over and over. He's good at getting intensity out of his players on defense but his players will eventually get frustrated with the fact they aren't getting open shots.