(1) He was more ambitious in terms of the scale of the work. I could (and did) sell and execute small consulting jobs that would have never made me rich but could have kept me cashflow positive. For him anything had to be bigger so he could get a commission. I did sell a few projects after he left and also had another collaborator for a consumer product startup who I didn't feel was listening to our subject matter experts so I gave up on him and got a job for somebody else's startup.

(2) As a team we were highly effective at getting calls and getting people to talk, often about things they shouldn't have told us. We found out a lot about the internal tools at startups, failing projects at three-letter agencies, cloud migration plans at the world's most secretive hedge fund, etc.

(3) The worst problem with this guy was that he was (at least sometimes) dishonest. One person who we were talking to warned me that he'd lied to him and I didn't take it too seriously. Then he lied to me in the heat of the moment and I accepted his apology. There was a third time that I went down to NYC to meet somebody I had met through all the marketing activity we had done and he told me how my partner had told him totally different things with him individually as opposed to the group and that was the initiator of the breakup.

Even if you're willing to put up with small dishonesty from someone or you don't take it very seriously you can be sure that it can have a deadly impact on your business.