I know you said that you liked hand knife over electric due to no plug in. Well I can say Rapala has a lithium ion cordless fillet knife with a 6" blade and a 7.5" blades, 2 lithium ion battery, charger and caring case and i have cleaned 100+ crappie at one time with no loss of power. This knife is amazing and once you get the hang of how to use it you can fillet a fish as good if not better than a hand knife and faster as well. Now when it comes to striper or catfish it works good as well but I tend to use a hand knife. Now i have used some of those knifes in your test and I do like them but I am using a knife from a small knife shop called ( Custom Cutlery & Ironworks ) now they have some nice knives for fishing, hunting and the kitchen. As you know there are many options out there for fillet knifes it just all depends on how it feels to you. For you people out there that are against electric knifes ( I was ) just try one you may be amazed.
YOU CAN'T CATCH THEM ALL ......... BUT YOU SURE CAN TRY!!!!!!!!