Of course, the strain of flu that is being vaccinated against changes each year while the bulk of the vaccine remains the same.
Regarding this particular vaccine: I have spoken with several healthcare professionals who have expressed concern over the safety of this vaccine. In part, that may be because unlike other flu vaccines this vaccine requires two doses. I am not a health care professional, and I don't claim to know any other differences between this vaccine and those that have come before it. However, I trust the professionals that I have consulted. They urge me to get the flu vaccine every year, and they get it themselves. They are concerned about this vaccine, and I trust that.
ETA - For my family it may be a bit of a moot point anyway. Swine flu has been in our county and our schools since last spring. In fact, we currently have the largest number of documented cases of swine flu of any county in our entire state. By the time we could get the vaccine, it's likely that we already will have been exposed to it, if in fact we haven't already been. As of last week, no place will even test for it any longer. We've all been sick recently; for all I know we could have already had it.