Having just done a roadtrip across Canada with an OEM partner to showcase our product, I got to have roundtable discussions with around 400 dealership representatives across 3 weeks of travel. As far as this question goes (at least here in Canada), the resounding questions we got were:
1. Bad Reporting - many dealers just expect that reports provided by the same vendor providing the product or service are tainted, especially if they have to be "prepared" and aren't available immediately
2. Poor integrations - many vendors say "yes" to every integration question and only after signing the contract do you realize that their idea of an integration is that you manually export the data and send it to them or you call the vendor yourself and tell them to make the integration work. Dealers want a much cleaner idea of what is and is not actually integrated.
Bad support also came up alot, but typically in the context of a few key vendors who have been acquired and downsized their support teams to the point where you can't get any support at all.