You can tell as you're having conversations. The points you mentioned mirror my experience. One the one hand you'll have an investor who is well networked and introducing you to enthusiastic investors, someone who is interested in driving the process forward and who has made many investments and where amount isn't an issue. They're more interested in valuation and terms. In my experience they also add value before you even close. These folks are modest, extremely accomplished and wicked, wicked smart.

On the other you'll have someone who has made few investments, where the enthusiasm level is low and where there's a lot of nitpicking and low quality intros to people with little interest but who wear expensive wrist jewelry.