there are good and bad point to both options,
alone - more time to compose and flexible
buddy - more eyes(or ideas) to catch unique angles and shots
i currently only go around with my colleague cum shooting buddy, as we both have very different thoughts and shooting style, not to mention different cameras, he has a Canon 450D while I'm a Nikon D60 user. but we're very open to each others view which gives us the chemistry.
if anyone wants a shooting buddy, and don't mind me tagging along, do PM me :-D