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A few things people should know (and I'm trying to be as objective as possible):

He gets offended way too quickly. One very strong example: At any moment in time I say something. If, after that moment (after a few minutes/hours/days) I write a sentence like "As I said, " it is a big offence to him. I have worked with people for all across the world and never heard that "as I said" is a note of offensive superiority. There are other examples but this is the one that actually shocked me.

He ended the assignment without telling me anything. Not even a "bye" or "thanks for all your hard work and staying up till 3 am". Nothing. Nada.
And he did it right in the middle of another discussion in which (I assume) he again felt offended by something even though I was talking about something else and when I pointed out what I was talking about, he probably got pissed or something and closed the assignment.

He is always right. Unless it's a delphi thing which is the only part that he admits he's weak at and somebody else being better and being right.

He appears to be a mediocre coder (no offence intended!!! but the following supports it) and if he makes a mistake or doesn't know something he says something like "it's a delphi thing and I don't know delphi too well". I *think* that in over 50% of the cases the issue had absolutely nothing to do with delphi. Guess what happened the last time I actually proved this? Yes, he got offended.
Which reminds me: when he does get offended like that, he "disappears" for a few hours. When he returns, completely ignores the last discussion and topic (EVEN if it is task related) and goes to something else. I think I got 2 of these disappearings before I got the assignment ended, so take it as a notice.

His account will be suspended nearly every weak. You will find this out after your first week and also the explanation that it's because some delayed payment. But the payments to you as a provider are done without delay!! 
However, do note that whatever you work (and you will) during the time his account is suspended is not covered by odesk guarantee. He will accept logging those as offline hours but still, it's a risk considering that you can get your assignment ended just like that.

Other than that, it was nice working with/for the guy.

PS: I would appreciate it if odesk staff would not cut into my feedback as all of it is hard facts and I have 5 months of skype and email conversations to back it up. The truth sometimes does hurt but that's no reason to hide the truth just so that a person would not get offended. Especially since I kept most of the subjective things to myself AND this particular person is very easily offendable. Thank you.