What is the difference between VC's and Business Angels?

As the story of the birth of Jesus depicts, an angel appeared before the Shepherds and guide them to Jesus. One difference between VC's and Business Angels can intuitively be seen just from their names itself. Business angels are thought to guide budding new entrepreneurs as they start up their businesses, and not just with financial capital. They usually play the role of a mentor and want to have hands-on involvement in the process. This is not to say VC's don't want to help entrepreneurs but, as I have heard, VC's tend to help out entrepreneurs when things are going really well or really badly. So why is this the case?

Before I answer that question let me just go over some of the superficial differences between the two. Business angels typically invest up to around £250,000 into a business. This was certainly the case for Innocent Smoothies when they received £250,000 to start up their business from a wealthy Business Angel. And Business Angels invest their own money into a start-up.
VC's on the other hand will invest between £1m-£20m into a business. They are only interested in high-risk, high-potential start-ups and as such look for high returns. The money that they are investing comes from investors such as investment banks and pension funds.

So a lot of the differences can be due to the difference in motivation between Business angels and VC's.
Business Angels are often experienced entrepreneurs who have "made it" in a particular sector. As such they may see investing in a start-up as a way of "paying-back" society or give a start-up an opportunity that the Business Angel may or may not have had when they started.
Business Angels usually have experience in one sector and as such they usually invest in that sector. Being involved in a new start-up gives the Business Angel the chance to "tinker" with new technology, which they may be interested in. This explains the need for a hands-on approach that Business Angels look for.
And finally Business Angels want to make a profit. They certainly don't view new start-ups as charities and they usually have to consult with one other person before they part with their cash... their wife (or husband).
I have hopefully shown that for a Business Angel there are more reasons for investing into a start-up than just the potential profit. Business Angels have intrinsic motivation for investing in start-ups and therefore are a lot more involved.

On the other hand, the top 3 motivations for a VC to fund a start-up is simple. Profit, profit and profit. This may be a slightly harsh view on VC's but it is essentially true. If a start-up is not going to produce high profits then the VC's will not care about that company. As for the VC's only helping when things go really well or really badly, VC's tend to tend have a portfolio of investments. As such they don't really have the time to have high involvement in every start-up and only help those start-ups who are struggling, to minimise their losses, or those start-ups which are really successful, so they can maximise their winnings.

I think a good thing to remember is that VC's aren't 100% doing it for themselves. While they do receive a substantial percentage on their investmenta, they are essentially an intermediary between investors of the VC fund and the start-ups. As such they need to keep their clients happy and the way to do that is to maximise the returns.
Business Angels are doing it 100% for themselves. They get to keep all the returns that they receive and don't have to answer to anyone (again, apart from maybe their wife)