I worked at 3 busy dealers and worked as a service adviser for about 5 years, and a technician for 5 as well, so take what I say with a grain of salt. I used R&R, ADP, and DMS for the duration of my time as an adviser and used DMS for my time as a technician. For terms of how easy each was to use, I have to say DMS takes the cake. You can create an RO in seconds and adding lines was easy. Also the scheduling is pretty straight forward as well with the ability to make an appointment, order parts against it as necessary, then create it as a repair order is nice. Also using it as a tech for notes is simple and requires minimal effort so you can keep your techs on cars and not fighting a shitty system. If your a dealer flagging for warranty is a snap, and managing warranty hours vs Cash vs Internal is a breeze. ADP also has a very nice scheduling system but is not as adviser friendly. I feel like everything I did even looking up customer data took an extra step. Also R&R wasn't bad but it wasn't very good either. I used Reynolds and Reynolds the least out of all of them, because our dealer needed something better. Also I think DMS had an app but im not sure, ADP Def had an app that you could access via tablet.