When the 575 and the 372 are both stock the difference in power is not significant, the 575 is marginally torquier but it is noticeably heavier. The 575 also seems kind of large and bulky but this may only be my perception. The 575 is a very smooth saw in the cut and it is comparatively fuel efficient. I don`t see anything compelling about owning a 575, I got mine when they first hit the market and I don`t expect to own another. I`m fairly disappointed in what Husky did with this saw to be honest with you, it looks as if Stihl has done a much better job with the 441 from what I have heard although I have not run one.
You might try different channels if your local dealers have no 372s, from what I understand the 372 is going to be available in Canada for another five years. I would imagine Walkers could hook you up that if noone else could help or maybe a properly modified Husky 359, 357, or Stihl 361 would satisfy your needs?