I would write out a post attempting to explain, but why bother when I can link you to a better explanation than I could ever come up with:
そうです vs. みたいです (with verbs) - Reviewing the Kanji - Learning Japanese
(This thread also has links to a few other threads explaining things even further)
And should you feel like reading a very vague explanation of it here it is on Tae Kim too:
Similarity or hearsay | Tae Kim's Guide to Learning Japanese
And for your future reference it is spelled そう(sou) not "so"