I have one of the Cork handled White River fillet knives the longer version. Very nice knife. They use the same size handle for both the 6" and 8.5" models. I thought the handle was a bit large for the 6" model. Some may prefer that. Also got my son one of the Kermode's as a gift. I didn't like the flex it had. Imo flex is good for skinning but I prefer little flex for filleting, particularly for fish with tough skin or larger scales (redfish). Again that's a personal preference. I'm a nut for fillet knives and have many. From inexpensive to high dollar. For small fish (and some larger) the Havalon Baracuta Z folder works well. Razor sharp! You can cut the snot out of yourself if not careful. I have a friend with stitches from one of these. He didn't heed my warning. They don't hold their edge real well but can be brought back to razor sharpness quickly with the Sharpmaker. I like mine really sharp so after a dozen or so fish I do maybe 20 passes and it's back to almost original sharpness. If in a situation where not easy to sharpen, replace the blade and keep going.
For larger fish the Bark River or Microtech Black Marlin both work well. I have one of Phil's Punta Chivato's, one of my favorite and most used knives, classic.. Some day I'd like to get one of the craftsmen on the forum to make me a custom of my design. Talked to a maker in Florida about 6 month's ago but he never got back to me. He's very busy and does mostly beautiful hunting blades. Dexter makes some good and inexpensive knives. I've had or tried many production makes and models. Always on the search for the perfect fillet knife. Wish Spyderco would do a run of the Catcherman's in LC, would like to try that.