Resolution is the other big one. A well set up big scope should always beat a smaller aperture instrument. You won't always be able to see the difference if seeing is poor, but when its great that's when the extra resolution (and light gathering) of the big instrument pulls away.
BUT, but instruments are big heavier, a PITA to set up (better in an observatory), very expensive, require very high quality (EXPENSIVE) mounts, usually require exacting collimation. They also tend towards longer focal lenghts with tighter fields of view that won't suit larger objects. You can get around this to varying degrees with EXPENSIVE correctors and focal reducers.
Astrophotography requires intimate experience with a number of key variables (tracking, balance, software, FOV, image processing, focus, etc) for success. All these things are very exacting once you get past a focal length of 1m. The 2m FL of the 10" will be challenging unless you have lots of experience and high quality gear.
Most people have a lot more fun imaging at under 1m until they've really been pulled over the imaging event horizon....
CCDcalc (freeware) is worth a play to get a feel for the effect of FOV with different scopes and cameras.
Judging by your website pics you're no newbie though....
