Depends on what you want to go into. If you want to go into specialty X, pick the site where you can get good grades and network with academic physicians who will write you letters.
If you just want to pass through, pick a site with reasonable hours and easy grading.
An example: I'm interested in a surgical field. I picked a community hospital with a reputation for huge operative volume and a "true surgical experience". It's been great. But the site is also notorious for harsh grading, so I'm banking on the shelf to pull my ass out of the fire.
What do you think future residency directors are going care about more: my likely pass to high pass in surgery or the fact that I rotated at hospital X?