richard sums it up well with "perfect", I look at M:I3 and it looks "right/perfect".
I watched M:I3 yesterday with a friend that hadn't seen it, we watched the DVD version because I wasn't willing to watch it with the poor sound from the add-on. Even though my friend didn't notice the SD picture because he hadn't seen much HD before, it was cringeworthy for me, it looked horrible, it totally blew his mind when I showed him the HD-DVD version when we had finished the film.