They are pretty different. Usermind is designed for much more depth in the use cases, where Zapier is designed for breadth of integrations. For example, Usermind automatically normalizes records across systems (not just api integration). So, if you have a customer in Marketo identified by a user with an email email@example.com and there is the same company in salesforce identified by firstname.lastname@example.org, Usermind will do the work to figure out that they are actually from the same company and this is the same opportunity (by using other information in the systems). There are dozens of other use cases that make Usermind and Zapier really different in their approaches and potential applications.