One question I would ask myself is that "Does he/she share the same passion as me on what the startup is trying to accomplish?" If he share your passion as well

One question I would ask myself is that "Does he/she share the same passion as me on what the startup is trying to accomplish?" If he share your passion as well, it is all good. Plus it is important not to have too many technical people on board, having a marketing guy would be useful to help you translate what the startup is trying to do to its potential users.