Bugs that I've just had:
1) Ambulance's that you set to patrol, go around in the oppersite direction of traffic flow. Causes incredible back-ups.
2) FDNY/EMS Only Call Outs sets game mode to Challenge. No problem. Until you get a Exploded Gas Line Call that causes 5+ houses to be on fire and 10+ Casulties which fails you automatically from the game without any chance of putting the fire out. When I mean automatically, I mean instantly. The call hadn't even finished coming through and it said "Fail - you have lost control of the city."
3) This goes with number 2. If you quit the game you're playing, try starting a new Freeplay Game or have what I just had, an incident that causes you to automatically lose, you have to go through the High Score listing page before you go back to the main menu. However, that doesn't happen. The second you hit that last button to either cancel and go straight to the main menu, or follow the buttons that take you through the high score listings, your game automatically crashes you to desktop. Which gets frustrating because this is a big mod and it takes some time to load the modification.
Steve, FDNY & EMS mode was an idea by dyson, apparently it doesnt work to my knowledge so just stay away from it for now. The Crash issue at the end of the game I just recently learned how to fix it. If you have windows 8 installed you dont have that issue for some reason. Also I read from a tester that if you delete the logfile before ending the game you go back to the main menu. So you can try those. For the ambulance you might be shift clicking the command which apparently makes the patrol path reverse.