Blips in the middle of a song are usually because of a transfer error using a protocol that doesn't check for transfer error properly. If you get decent entire-album releases in one archive/torrent, they're almost always tagged correctly. That's what it is like for me anyway, almost all the albums I've downloaded the last 4 years have been tagged correctly. The stuff that haven't been tagged correctly have usually been single files that I've gotten from filesharing programs like limewire and the like.