Isner and Murray are the most impressive. No surprise to see the top spots occupied by people who played <15 tiebreaks, winning a high % after playing 20+ is a lot more difficult.
the carreer recordman has played 52 tiebreaks : Pablo Cuevas (73%, that is 38-14)
only player with better stats than Fed among those who played more than 50 tiebreaks as far as I know.
Unfortunately injured this year