Rio is very overrated in his on the ball abilities. It's been quite awhile since he was any good at playing the ball out. Evans is miles ahead at it these days.
He is slightly overrated, not very. There is a reason why attackers were given a job to close him down when he was on the ball. That was because his long ball distribution was very good, he was also terrific at running through the midfield. I agree that Evans is better at this now, but even he lacks that power and pace that Rio carried. Evans distribution from a CB position is nigh on world class though - lacks in other departments, unfortunately.
I criticised a poster for discussing who was the better player of A and B because he claimed B was a better player but A was a better striker (I think it was). To me, Rio is the better player of him and Vidic, but Vidic is the better defender. Overall, that makes Rio better, imo. I'm talking about their primes now, and I'll try to explain why:
1. Rio's pace was unmatched. Some of you claim that Rio struggles with quick players, but Vidic has struggled much more. There's a reason why Torres always chose Vidic's side, same goes with many quick defenders. Because although Rio has lost a couple of steps, he's still quicker than Vidic.
2. Rio's reading of the game is terrific. The fact that he can go an entire match without making a sliding tackle just shows how brilliant he reads the game. Vidic is a stronger tackler, no doubt, but sometimes I think Rio is wiser in his decision making.
3. Passing and technique is another area where Rio is the better player, imo. Vidic has improved tremendously, but he clears the ball to a throw-in or a corner much more often than Rio does, which, imo, is something that often goes unnoticed with Rio.
Vidic is a stronger tackler and a better header of the ball. At his best, I still think that Rio is the better player and because of his pace and technique was also the better defender. In terms of pure defending attributes, Vidic probably just edges it though. The most complete partnership I've seen, no doubt! (except for Skrtel and Agger of course)