Did you ever try a custom ROM to see if the issues would be resolved? It's hard to get something replaced when you can't prove it. Otherwise anyone with an Evo could make phantom complaints and get a new Evo whenever they wanted. Gotta see Sprint's side on this.
I have constant issues with Facebook not syncing real time or close to real time on all of my Android phones (Epic, Evo, Moment, Vibrant, Captivate, Optimus) - I chalk it up to crap Facebook (I do hate FB but need it to look at family photos).