I didn't rate him that highly for many years but during his latter years at Barca he had definitely developed into a top-class goalkeeper. At least on par with Lloris and much, much, much better than Asmir Begovic. Are you saying that Begovic is better than Valdes ever was?
I have previously advocated buying Begovic as a fall-back option. We could then start Valdes and give him a chance at rediscovering his old form, and if that doesn't work, Begovic would be a perfectly decent plan B. I just think it's a waste to spend 25-30 million on a new goalkeeper when we have a potential top-class keeper already in the squad.