There's really no big difference between the 1080 and the 2080. The 2080 has a bigger display, which is useful but not necessary (especially not when you're using a computer for sound-editing). A 2080 can be expanded with 8 ex-boards, a 1080 with 'only' 4. The 2080 has 128 more sounds, and 3 EFX-effects instead of 1. If you're a beginner, i'd really choose the 1080. It has the same (excellent) sound quality, and has already so much features and sounds that you must be terribly intelligent to remember them all!
You could also choose a Sc880 which is easier to operate, has even more sounds (1200) but lacks the editing
have luck!