I have a Rapala brand that hooks to a 12v battery or can be plugged in the wall with an adapter. The blades are not that fast, but they are powerful. Will cut through the ribs if a 2.5 pounder like butter. I think it cost about 50 bucks. I also bought a Hamilton beach plug in only from the home section of wal-mart , and it works great and for half the price.
My experience has been that they all get HOT if u are cleaning 20 or more fish. What I do when cleaning a bunch of them is use 2 knives.when one gets too hot, put it down and use the other one.
My favorite method is to clean fish till the knife gets too hot, then stop and drink a cold beer and let it cool off. By the end of the fish cleaning session I will be doing all right! Sad thing is I have not gotten to use this technique yet this year due to uncooperative fish and weather.