For a countertop model, the Cabelas branded one is pretty decent….just don’t overload it or you’ll drop the temp in a hurry. Mines lasted a good while but I don’t abuse it. For really quality stuff you’re going to be looking at gas, with serious BTU’s and serious dollar signs attached to it, not to mention weight and general bulk.
if you really want a killer unit, go check out some restaurant supply stores in your area. Good stuff and robustly built, but cheap and portable they are not.
the last thing I’ll mention is that people don’t clean their fryers enough. Not just the main assembly, but in the components area as well. Get in there periodically with some potent degreaser (check your gun cleaning supplies) and clean that sucker out. The amount of gunk that gets in there from splatter is staggering.