Could someone highlight major differences between the two versions?
As others have mentioned it has been a while but here are some notables:1. tinyMCE (SP1)2. XSLT presentation templates3. New Roles and User Model4. Folder permission overrides5. New Workflow ModelerIf you are considering an upgrade then 6.7.2 SP1 would probably be the way to go since that included integrated SitePublisher install which is not part of 6.7.1.
I heard that SP1 is not good and one should be avoiding to install it. 6.7.2. seems to be Ok.