I am new at the Barrow Downs, so...
Hello! 
Here's what I personally think of the
Sauron versus the Ring issue:
Sauron originally possessed great powers as a Maia. And with the creation of the One Ring, he simply poured
himself into it; for I believe that Maiar were able to extend their animating influence to more than just one body. They were angelic beings whose true forms were unseen by the mundane peoples of Middle-earth - meaning: they were formless.
Yes it did seem that some of the Maiar were subjected to one body, as in the case of Gandalf. But still... maybe Sauron had learned some other forms of art from Melkor. The latter was, after all, the mightiest of the Ainur.
Therefore, I think Sauron and the Ring were one and the same.
Or... it could be this:
Sauron and the Ring were not one and the same. Remember Tolkien's philosophy towards technology and materialism, and their
powers over the minds and hearts of people?
Well, the Ring symbolized the dominance of technology; and its apparent influences over its recipients (including Sauron) was no different than a man being addicted to... say... a computer for instance.
The recipient's intentions may rise from a good will (e. g. Boromir), but in the end, it will always be power and dominance and technology.
So the Ring did in fact have power over Sauron.
Anyway, I may have repeated someone else's comments; and if so, then I sincerely apologize.
- Philomythus