If you just wan to use your scope for visual stuff, I'd recommend you go with the 8SE, it'll be easier to set up and use and therefore you'll use it more.
However, if you ready do want to do some imaging then the C8 SGT is the way to go. No field rotation, but it will take a little bit more time and effort to setup and polar align for AP. A simple compass alignment will suffice for visual work.
I don't understand the "slightly better light gathering" comment for the 8SE... they are both 8" SCTs we are talking about aren't we?
Al.