I wonder do any of you use the fishlocker knives (539, 549, 559), because this knife folds but is substantially lighter and feels a bit cheaper than the TruBlue...IMO or do you like just a fixed blade filet knife. I actually prefer a fixed to a folder...
For me, the choice depends entirely on where I am, what other stuff I'm carrying and how the stuff is being carried.
In the field, I strongly prefer fixed blades for actual use. I can drop a fixed blade in the mud, muck and sand and then swish it in some water and it's good as new. Opinels seem to be the most dirt & muck tolerant locking folders that I own, but all folders, my Bucks very much included, protest when I drop them, use them or even carry them in dirty or sandy conditions.
This said, I almost never take a fixed blade and almost always take folder. I won't hike, hunt or anything else with a fixed blade hanging off my belt. But for me, I just hate having anything on my belt to begin with (a YMMV thing) and I especially won't do it if I will be carrying a backpack or fanny back with a hip belt. Folders go in pockets and the big and/or heavy ones take less space in my pack than a fixed blade. Much easier to manage in the field to as their is no sheath to loose.
Fishing tackle boxes are one of the few places where I still carry a fixed blade knife. I drop it in the bottom compartment and if I need to clean a fish, I have it with me. I could see a fixed blade replacing my Buck 110 for hunting but don't feel the need for that. Either way, the hunting knife rides in my fanny pack.
All this to say that for me, carrying trumps performance (of the pivot/lock).