Coming from iDrive you will also likely find Mercedes COMAND and the in-cabin tech a little trustrating, especially if this is your first Benz. For instance while every setting in the BMW is controlled through iDrive the Benz splits settings between COMAND and the instrument cluster. You will also find some cheap and nasty materials in the CLS where you wont find them in the BMW (climate control for instance).
All of this is subjective though and ultimately down to your personal preference. Heres an interesting
comparison of the GC vs CLS vs A7