There is a balance that needs to be created at the outset between those that need the finance (the "Operator") and the Angel/Investor . The Investor would have no investment without the Operator but, conversely, the Operator would have no business without the Investor. Although there maybe an inequality in funds, there is a definite equality in the generation of profits and wealth. This "equality" has to be created and governed by a shareholders agreement and amendments to the articles of association of the company.
Unfortunately, I regularly see situations where the parties have adopted a go it alone approach and have then fallen out without the basic agreements to act as a safety net. It is in these situations that the true costs can be measured as, all to often, it can bring down a successful business.
What is the experience of other members of the Group?