Based on people I work with, I'd sum it up as follows:
Boomers: Mostly argumentative and difficult to get along with (which is not always a bad thing...) but are solid workers.
Gen X: Some are very good, but many tend to be overly cynical and negative especially when dealing with problems. Many avoid voicing their opinion. The least likely to take unnecessary and inappropriate risks.
Gen Y: Generally good at dealing with problems and optimistic but some (not all) need a push to maintain productivity. Generally unwilling to heed advice. The
least likely to "cheat" and avoid work. Tend to take inappropriate risks.
Who would I employ? To be perfectly honest, age is a long way down the list I think. Much higher up would be to avoid employing smokers. It's not the time they spend smoking that is the problem but that smokers, particularly Gen Y males, tend to have attitude problems in general. Not all of them of course, but there does seem to be an association in my experience and they're best avoided.