freeflow. I will preface this with, I work for Mares and our other brand (Sporasub... freediving and spearfishing equipment). I'm also a freediver and Scuba Diver for over 20yrs. I mastered a live aboard dive boat in S.CA.for a long time. I spent countless hours freediving and spearfishing, everything from lingcod to white seabass, and yellowtail. I've tried and seen a lot of guns. Some were terrible and others beautiful. As I mentioned earlier, pneumatics are quite popular in your area, not to say other guns or polespears wont work. You didn't mention anything about polespears though.
I sell many Mares branded pneumatics (sten) series)). To quite a few of the dive shops in your local market. Sound Dive in Bremerton or Underwater Sports being the largest and with product in stock, most sizes, and usually a very cometitive price. Should you decide on a pneumatic, you will find many brands online, but very few locally. Not because I work for Mares but I feel we build the best pneumatic, longest lasting, powerful, quality gun, and have service nearby.
As far as whether you should have a polespear, pnuematic, banded, JBL, Euro, IMHO this is a personal preferance and is debated all the time. All will work fine for you. Polespear definitely adds a different dimension of challenge. Banded guns you will be replacing bands, and wishbones, Pneumatics you may have to get serviced 5-10yrs down the road. Never heard of or had a problem w/ pneumatics in cold water. Like I mentioned I've not only used but sold many into your area and believe me if we had a problem with cold water I'd have had more than an earful from my accts. Do you like the look of the sleek euro's over the big clunky jbl's as described above? Euro's shoot faster, and more accurate than JBL. But then again your shooting mostly into holes and sedentary fish so not as important. Downside to Euro's in your neighborhood is they are relatively uncommon, so unless you know exactly what you are looking for, parts and accessories will be hard to come by. I prefer the Euro to JBL but I've got all the parts and I am familiar with the product.
If you are on a budget spend your money on what you like and can afford. You can definitely get a Sten pneumatic for around the same price as the NW special. Don't know about the Valentin other than they are not nearly as prevelant as the other two mentioned. Bottom line is hurry and get what ever and get out there and put the food on the table.