A lot of variables go into determining the outcomes of your 3 important to me factors.
For example, your tuner's ability to utilize fail-safe's and incorporate that into the Bosch ecu decision making is a big factor in reliability. Outside of that, good general maintenance and up keep of a high performance car such as the F8x is the primary factor linked to reliability.
Ease of use has to be further defined. Do you like data logging and going back and forth if running a custom file? Some do while others just want to get out there and not interested in doing it. You're not likely given any control to change critical parameters like boost target, timing advance, and other critical parameters so it's all really "easy to use" in my opinion ... once it's flashed onto your car go out there and drive it. I think it's the process and communication back-and-forth with your tuner (if custom) along with making adjustments to your tune is where you might ask yourself and define what "ease of use" means to you and your goals with the car.
Lastly, most if not all typically flash back to stock. How much of an imprint each tuning software platform leaves behind will vary.
Hopes this helps
