Both, and neither.
"Hits" is not the best measurement to start with. "Unique visitors" is more meaningful, but it depends on how the package in question defines a "unique visitor." Abandon rates, exit rates, conversion rates, visitor paths through your site... there are many better things to be looking at than "hits."
Analytics packages are almost all different in at least some small respect. Not wrong, just different. Compare six different stats packages and you'll likely get six different sets of numbers. Doesn't mean any of them is necessarily wrong (or right, for that matter). Just that they have different ways of collecting and analyzing the data and different ways of reporting what they've found.
The best thing to do is not to compare one to the other. Pick the one that gives you the kinds of information you can use and displays the data in a way that makes the most sense to you, then use it to discover trends over time.
The idea is not to try to figure out absolute traffic ("We had 850 visitors yesterday!") but to track trends ("Our traffic is up 20% since this time last year!") and to use the reports to discover "sticking points" and poorly performing pages within your site so you can improve site usability and conversions.
Because that's the whole reason to look at web analytics reports. Not to pat yourself on the back because your analytics software says you got a zillion hits, but to use the data to improve your site so you make more sales or generate more leads or get more newsletter sign ups or whatever it is your site is supposed to be doing for you.
You might also want to take a look at the book Web Analytics: An Hour a Day
by Avinash Kaushik. He's a real guru of web analytics, the book is an easy read, and following the exercises therein will DEFINITELY help you better understand what those numbers on your reports mean (regardless of which analytics package you use) and how you can use them to improve your site's performance.