Pros
Has computer-based training available so you can improve your skills; jobs are usually available with little delay, and some are long-term. I have had positions as short as a single day and as long as five years, with one company keeping me within various departments for two decades.
Cons
The business model for Manpower, particularly in the Virginia suburbs, appears to have changed -- what was once a source of good employment with decent salaries and a company that acts as YOUR agent, constantly pushing the company you're assigned to for better pay and assignments, now seems to have joined the race to the bottom; assignments once earned me $38/hr plus - now I am given assignments typically in the $10 - $20/hr range even for long-term assignments, and the company doesn't seem interested in trying to improve on that. Add in that vacation pay, once two weeks if you were able to meet the threshold number of hours, has totally disappeared. When the full-time employees that surround us at our assignments are making $50K to $60K -- that's roughly $20 to $30/hr, plus excellent benefits on top of that including vacation, personal time off, sick leave, REAL retirement account matching, etc., it's hard to see any rational course but getting out as quickly as possible, and that's what I have done..