I'm just torn to pieces over two employees of mine

I'm just torn to pieces over two employees of mine. I have Dave who is so nice with the customers, great smile and even sucks up to me which at times gets on my nerves. I also have Don who has been with us 2 years too. Don is really a character and is rude at times, seems to lack tact but, has a natural ability that has opened many aspects involving our company business, plus financial and political areas. I have never had an employee as gifted prior but must let either Dave or Don go as the company is expanding but during transition must cut jobs. Should I keep the one nice guy who I like as a person or keep the other employee who is making the company money? i decided to keep my feelings out of my decision therefore I must send Dave down the road and keep Donald J Trump.