I don't have an external HD setup, I'm just playing directly off the system.
Well the first thing I did was I went and played the first level because I remember that being pretty bad and there being one or two parts where the game kinda freezes for a second. That doesn't happen anymore, but the frame rate overall is still not completely smooth. After that I continued from where I had left off last time I played, which was 3-2, and then level 3-3 until I reached an area where I was stuck behind something and had to restart, so I just turned it off.
It does run a little better post-patch, but I was expecting more, I guess.