Wealthy entrepreneurs or entrepreneurial/investor families (think family offices) can be good, if you want to raise third party capital. They usually take a longer term vision than a VC would, since they're basically one of the groups of people VCs raise from.
I'd prefer working with those over a VC any day of the week if possible. They're usually bring a lot more value to the table.
Well, maybe. I guess it depends on how you look at it. There are angels who spread their risk significantly and invest in a ton of startups (think, Ron Conway).
Then there are wealthy individuals/families (e.g. Bill Gates, or the Walton family) who have less formal investing guidelines but occasionally back good entrepreneurs. This could be through seed capital, growth capital, or capital for a private equity style leveraged buyout. Raising capital this way is much more about relationships than the VC game is. It's a lot less formal. These people usually want to (help you) build sustainable companies, nit you're not really competing against a ton of other people/deals (like you are with VC firms). Even if someone came to them with a decent idea, they probably wouldn't back them.
I'd prefer working with those over a VC any day of the week if possible. They're usually bring a lot more value to the table.