From my marketing position at my previous store, the DMS was one of the few technology systems I did not admin. That said, we did transition from Reynolds to ADP with only minor issues. Months after the switch, there was a general consensus that it was a good move. One interesting advantage to a DMS change is that you are forced to reevaluate all of your processes. You'll find that some people have been using work-arounds that may or may not have been necessary which result in less accurate data (or worse?) I know that money was the original discussion point, but Reynolds all but mugged the dealer in a store acquisition and we came really close to switching mid-contract. That Reynolds' retention plan is based on contracts rather than customer service is unfortunate. Data was not a crisis, but the integration for the CRM (VinSolutions at the time) became a surprise added monthly cost. Be aware that ADP seems to charge for the most basic of integration, including linking data between some of its own products.