I once dealt with a sophisticated investor, though with no experience in tech investments. The idea of a convertible note was foreign to him and thus unacceptable. He wanted to own preferred shares right away, but I wanted to avoid lengthy and costly negotiations and giving away control at that point.

We then discussed a middle ground between the two: the investor gets common stocks without any special rights except anti-dilution and an option to convert them to preferred at the time of the series A round. This way we could achieve many of the benefits of a convertible note, such as reduced legal costs and the ability to close faster. Eventually we didn't close that deal, but it seems that it could have been an interesting middle ground.

Has anyone ever done something like that? Is it common? I'm interested to know how it turned out and if you'd do it again.