what's the difference between picking the framework or the dylib library?
There isn't much difference in fact.
If you ship your application as un bundle (.app) like most application are currently shipped, then
it changes nothing at all because you can copy both dylibs and frameworks into your application. This make the installation process very easy for the end-user : she/he has only on action to make in order to install the application on her/his system. Copy/Paste yourApplication.app into her/his Application folder.
The "copy-frameworks-or-dylibs-to-your-app-bundle" phase is automatically created when you create a new project from the provided SFML templates in Xcode.
On the other hand, if you decide to ship your application as a simple ".exe" (there is no such extension on Mac - the executable name will be "yourApplication" on Mac and "yourApplication.exe" on Windows) then you have to install the dylibs/frameworks into specific repositories. This is the only difference : dylibs goes in /usr/local/lib and frameworks goes into /Library/Frameworks/ folder. That's it.
That's the general story. But with SFML there is another difference between frameworks and dylibs : you can compile SFML as a dylib library in both release and debug mode but only release mode is supported with frameworks.
Note that you can also build SFML as a static library (pretty much like it's done on Windows I think) but this is NOT recommended (if you're interested why this is not recommended I let you use Google search tools :wink: ).