Would you go into business with this person?

Two of us are going to launch an app. One is a surgeon, the second person is me with marketing and filming skills within this area of surgery. It's the biggest no brainer in history and the only question is who else is doing this. There will likely be other people developing this and I suspect it'll be a race to see who can get out to market first.The market is super limited but incredibly high value and extremely specialised. The surgeon is one of the best in the world and when we tested the concept with a couple of specialists in this field, the reaction was instantly positive. They told me they'd use this without hesitation as it would condense 3 - 4 days of medical work each year into 3 - 4 hours. It would make it much easier for them to do their jobs as it would enable them to do this part from home.There is a third person we are thinking about bringing on board. This person runs a small tech business. They could build this and reduce build and maintenance cost to zero. The issue is he overcomplicates things, is bad at explaining tech to non techies and has an ego. We can absolutely trust him commercially in that he won't run away and develop it himself or try to fuck us over. But he's difficult to deal with because he has an ego and wants to do things his way.So the benefits are we could get up and running very quickly at zero cost, trust him not to mess us around commercially but he's painful to deal with. He will miss deadlines, overcomplicate and his ego means he can't deal with criticism. Would you take him on board? see hubwealthy.com/wealthy