I think one key thought many are emphasizing is to not get caught up on any candidate over one game or the most recent thing you've seen, and I would agree with that.
A lot has been said about Daboll and other cacnddates' records prior to the current stop. In Daboll's case, many say "he's only done it with Josh Allen", giving Allen all the credit, and not considering Allen's improvement can be somewhat due to his coach.
Keep in mind, a coach who does not have the players with a high enough level of talent to run all his plays can't call all the plays he would like to. What good does it do to put into a gameplan plays a QB can't make?
I want a coach who can scheme around a weakness, so my QB doesn't get killed taking deep drops with a terrible O line, for example. I want a coach who isn't so stubborn he will keep calling his "pet plays" in spite of the personnel who may not be suited for them.
Some have pointed to Daboll not running enough which to me seems like a legit concern at times. Others post that they want an OC that will "emphasize the run" which makes me think - fairly or not - they are stuck in the 80's. The NFL today is about passing the ball. That doesn't mean the ability to run is not a plus, but any OC or HC who says, in today's NFL "we get off the bus running the ball" needs to be shown the door.
In short, if the Bears are fortunate enough to literally be choosing between Daboll and Harbaugh, we will all be pretty happy.
I think we overstate the offenses under Harbaugh, but he has had team success to be sure, and he has clearly, at the very least, proven to be head coach material, which is always a question mark with coordinators getting promoted.
We can nitpick any coach's success - Harbaugh had Andrew friggin' Luck at Stanford for example, and Daboll has Josh Allen. (Interesting to point out however, a year ago, Josh Allen was being questioned as to whether he could ever be the guy and suddenly he's Brady 2.0!)
If a coach has been successful when he gets the guys who can run his sytem, that is what we should be looking for. Not knocking the because they "only won when they had guys who could run their system".
The Bears need both. No team wins without both. First, get the coach who "can only win with guys who are good", and then get those guys.
There are a lot of coaches who do NOT win with talented personnel. Let's not diss the guys who are succeeding.