I have all three options in my car (it's an 08 though), and I can say that the HK system is pretty outstanding as far as stock systems go. Comfort Access is a complete joke. BMW really missed the mark there. There are a lot of complaints about the key fob range, which seems to change from five feet one day to as much as 15 feet another. You also will have to manually unlock the car most of the time by pressing the fob button, which negates CA's purpose of being able to walk up to the car and have it unlock for you by grabbing the handle. If you walk up to the car and expect it to open every time just b/c you have the key in your pocket, you will be sadly disappointed. When inside, 9 times out of 10 I need to remove the key from my pocket as the car won't start due to "key not found". Apparently, my jeans and dress pants I wear are far thicker than those BMW used during R and D of the CA system and block the RF signal completely. I have replaced the fob battery and it did not solve the issue. Other manufacturers are way ahead in terms of features and functionality of their keyless systems. The only cool part is the folding side mirrors, which can be handy in crowded side streets, or pulling up to certain drive up windows. I wish I could remove the CA feature from my car completely and go back to a keyed ignition, as it truly is useless.
PDC is ok, and does work well, but it's just not necessary.
HK all the way
