Do you think it is good or bad my bosses are alternating my position at work?

I work in a restaurant as a bartender. I am probably not as good as some of the other guys. Any ways the last few weeks they have had me as a waiter and serving tables, so I have been getting less hours than the rest of the guys behind the bar.

Would you view this as a compliment or a result of not being good enough to keep up

saying in a nicer way, it is job rotation; in another way it may be looked as misuse your potential ability. =P
try to look it in a positive way, you can learn more when you have the chance to try out different roles.