From what I understand the internals are different between the two, and some people have indicated that performance varies between the two. SublimeLinter includes Objective-J support. sublimelint is turned on all the time, while SublimeLinter has to be turned on and can be run manually.
I has to mess around with my php ini settings before they started working since short_open_tag was off locally. Both seemed to “just work” for Python, but SublimeLinter includes PEP8 checking by default. I believe it can be disabled.
For more information you can use the Discover Packages commend and visit the pages.