The 10" IS a lot bigger (well, bulkier at any rate), and heavier.
Unless you are going to be transporting it to dark-sky sites where the extra 2" will come in handy, then I'd stick with the 8".
I've got a 12" SW collapsing dob, and it only gets moved with the help of my RTV!
Mind you, I'm the wrong side of 30, so the bulk may not worry you so much.
