this year's blowfish has pads on the back of the bag to give some airflow space between the pack and your back. I know the 04 models didn't seem to have it and I'm not sure if they've done it with the HAWG or not, but my Blowfish has it. I do wish the blowfish had tie-downs and straps on the outside. The pockets themselves are quite useful and I like it a lot, I just wish it had a little different configuration. I also do like the expandable part. I do wish it was a bit more water-resistant, though. Aside from the lack of exterior tie-downs, that would be my biggest complaint about my camelbak.