The difference is iTunes Match will scan your ripped music, identify matches with iTunes Store offerings, and make those songs immediately (ok, give it a few minutes) available on all your devices - rather than having to upload all XXGB of stuff over a prolonged period.
I could have my 46GB collection synced with iCloud by tomorrow for $25/yr. Amazon will cost a lot more and take a lot longer.
I’ve got 20GB on Amazon and it didn’t cost me anything. So what if it takes a little bit to upload?
That’s what a 50/50 connection is for.
And considering iTunes can’t even find the album art for half my music for some stupid reason, good luck with it actually matching the entire song.
So, I could go throughh the tedious process of ripping all my old vinyl (much of which I never got around to duplicating on CD), and music match would upgrade it to high bit rate CD quality?