Mr. Dilworth left office when I was 6, so I cannot intelligently comment on his mayoral leadership qualities.
twickster-You do realise that Mr. Rizzo was a registered democrat in 1972 and 1976 during both successful campaigns, and only failed to win over Wilson Goode in 1988 by less than 20K votes after switching parties and running as a republican. 
Did you support him as a “rabid Democrat” during those races? 
Doc_Cathode-I have no problem with Mr. Rendell. While it’s beyond denial that Frank Rizzo was a friend to law enforcement, you should note that it was under a black mayor’s watch that the second Move incident took place. My recall is that Frank preserved law and order, and didn’t give a hoot about the color of your skin. Your allegation of “clubbing the crap out of blacks” doesn’t seem to stick, IMO.