A Good Relationship
Some vendors require you to contract separately with their credit card processing vendor and a separate auction provider, in addition to their fundraising platform. Your CRM, in this instance, is likely its own set of administrative work, too. That is multiple demos, contracts, reviews with legal, contacts, payments, and wasted time.
Look for a vendor that streamlines the purchasing and set up processes. As a partner in your success, the vendor you choose should make things easier for you, not harder.