I frequently fly ATL-ORD. I made 5 round trips this year.

ATL-ORD route
-One to three daily service on UA metal
-Two to five daily service mostly on CRJ700 (Shuttle America, Mesa and Skywest) - sometimes Embraer 170 (Shuttle America)
-Zero to two daily Embraer145 (Expressjet) - no E+

I am trying to avoid Expressjet since it does not have E+. Also, I found out Skywest uses Terminal 2 Gate F at ORD. I had to go down to the ground to board the plane, which was inconvenient when traveling with a baby. Additionally, I liked 3F on Embraer170 better than 3F on CRJ700.

However, is there any big difference between Shuttle America, Mesa and Skywest? (e.g. on-time performance, service)