I have a Rapala (Model PGEFR) This year will be the 5th year I've had it. Athough I do have replacement blades for it, I haven't had to change the bigger one, but will be replacing the smaller one I use for perch this year because it got well used over the past 4 years. It's cordless and came with 2 batteries. I can totally drain any remaining charge each battery may have by pushing a button on the charging base, and then once drained it will charge them to a full charge each time.
I charge them 1 the night before and 1 the morning of any fishin trip I've planned so that I have 2 fully charged batteries when I get home to clean any fish I've caught that wanted to come for a ride. (when doing a limit of perch that comes in handy, but generally one battery will do if I have less than a limit.)
It's worked well on any species of fish I've brought home for the freezer over the years. Walleye, perch, catfish, pike, rainbows.
But as they taught me way back when I was cooking for a living, it's not the knife, but how sharp it is, and more importantly, the skill of the person using it, that determines how well a knife works.