Graphics look a bit cleaner. And they added a bunch of effects like mentioned above. But overall the graphical difference to vanilla skyrim isn't nearly as much as a difference between what they gave us as 'screenshots' prior to release of SE. I haven't had any problems with getting the game to launch though. Heck it even runs more stable for me now.
Overall I'd say that until SKSE is adapted for SE, and the top quality enb/reshade/texture mods become available, it's not worth switching over at all. The vanilla version just looks better with what mods are currently available for both. That being said, once those things ARE ported to the SE edition, I can see it being/looking better than vanilla.
Imo SE should be seen as "a free small upgrade once mods are ported over" if you have all DLC's, or "A better version of Skyrim to buy, once mods are ported over" if you don't own any of the games yet. Not as a proper remastered release.