I wouldn't touch that Samsung 71 series. Its well over a year old, along with the Sharp 82u. Is there any particular reason you are looking at outdated sets? That Samsung has had many problems. You should be looking at a 650 series Samsung (current model). The Sharp 82u was also not a true 120hz tv, and was plagued with serious banding issues. I checked into the Sharp when buying, and all 4 had banding issues. I bought three of the Samsungs of which you speak, and will never buy another Sammy either. Finally settled on a Sony. Now I can actually enjoy a problem free set, and not miss countless hours of work time dealing with Samsung service.
In all honesty, I can't comment on the 85u Sharp. I consider them behind the curve when it comes to LCDs, especially after last years QC issues.