Personally I think that Sharkscope is very accurate (for SNG's). However, they didn't track MTTs until fairly recently & not all games are tracked.
Other sites are very accurate, aside from not tracking most of the priv. mtts (although some are tracked on some of the sites). By far the best imo is TopShark (although they do miss some tournaments on occassion but much more accurate recently).
As far as PTR goes (the site SB was making reference to), I'm not sure what's up with their tracking methods... as I've seen some large discrepancies. They have added a cool new hand replayer though, lol (great seeing how one of my neighbours plays their hands..... helpful for the weekly cash games here, lol)
Brad Booth - > "Like a fight... it's not how you start, it's how you finish"