With angel investors, the first very important attribute should be -- are they truly professional, accredited investors? Only work with professional investors who properly know how to manage the transaction so that it does not encumber further investment down the road. Angel investors have various motives and drivers that will get them to become a partner in a company.
Unlike angels who work independently, venture capital funds are managed by a team of people who answer to shareholders. The VC group goes out and raises a fund themselves, targeting a specific mission. By the time a potential client is being considered, there is a council of voices that must be attended to and reasoned with. So the experience is much more institutional, with layers of process. Obviously, smaller VC funds are more streamlined, but for the purposes of this discussion the difference between working with an angel and a venture capitalist is generally individual versus group.