All of the major US carriers have pretty similar and very good safety records. The delay you experienced is evidence of that. The fact that they're willing to delay a flight for so long to fix minor problems is a positive sign. It's the airline that says, "oh, it's just a wiper, we can fly anyway" that should be avoided.

Since the flight eventually left, and you were on it, you don't have a whole lot of leverage. I'd probably take it, although it won't be much use unless you fly Delta again.