Question for RE Agents that specialize in working with investors

I guess the specialization part isn't needed, but I was wondering what some traits of your ideal investor client would be. I've seen a few comments recently where Lenders gave a little insight into what they'd like to see from an investor. I'd be interested to hear an Agent's perspective. 

Edit: I think I should add that I'm most interested in the buy and hold rental side of REI. Also, I guess I wouldn't mind hearing from some wholesalers too.