Multisite vs. stand-alone install question

Thanks esmi, Amy and Ipstenu. I have a customer with 9 locations (and growing) and all would use the same theme, except the content is different (targeted geographically and modified enough to avoid duplicate content). I assumed multisite would allow me to use the same theme across most of his locations. I can set up 9 installs of WP, one for each domain (and stay within my comfort zone) but thought using Multisite might be the smarter choice. The sites need to appear (seamlessly) as different domain names. Any advice is greatly appreciated.