I recently took my PM9 on a three day canoe tip. I had the Khar in a camel pack. There was a lot condensation off the bladder, combined with the 3/4 of an inch of water in the bottom of the boat caused my khar to get very wet for 3 days. every night i would just wipe if off with my towel and set it out to dry.. After 3 days of being wet the khar didnt have  a spot of rust, discoloration or anything. I cant say that for my ruger  .22/45 the ruger had a few spot of surface rusts by the third day..

The black finish was definately worth the extra money,in my opinion.