I'm speaking with ZERO experience on this topic, but a Shakespeare company I worked for, for a number of years, uses "Theater Manager" - the website is
http://www.artsman.com/They seemed to really like it, though I would remember seeing staff-wide emails saying "everyone log out of theater manager, we're going to restart" or something. But if you're small, it may not be that bad. It was a smaller-staffed company and it worked for them.
But it looks like you have TONS of options from all these suggestions.
Good luck!