Lt. Bob is spot on with his comment about "20 times." That's what I said when I read your post....only 20? And then I saw his and laughed. Man, mixing is AN INTEGRAL PART of the process, and, in my opinion, should be given the same attention as writing it.
As for you song, it's very nice. And it's not a bad sound at all. And as far as whether it's beyond demo quality, that is really relative to what your target is. For example, if you're about to go in to record an album with Dave Mathews' record label, it's demo quality. But I think you did a great job. You're just not done ;-)
There's some nice strumming in this. Someone knew about dynamics and accents. I think the levels are good. It could use some EQ experimentation, and perhaps a teaspoon of reverb.
I'm trying to hear if there's anything I really don't like about that electric, whether it belongs, but it's not annoying. It sounds good in fact. But I'm not sure the stereo placement is ideal...maybe see if there's a better spot open left to right.
Nice song!