Well, the thing about extracts is that their quality varies greatly. It's just a guess, but I imagine the extract sold with a lot of kits is some of the lesser quality extract than some of the brand-name stuff. Fact is, a lot of extract makers add complex sugars that are not malt sugars to extract. It's misleading and crappy, but there it is.
I would continue trying different types of extract until you find one you like. I would stick to dry extract rather than liquid. Liquid will have more unfermentables in it. Maybe try coming up with your own recipes and buying ingredients. That way you can get better brand-name extract. You'll find that if you make the same recipe over and over, changing only the brand of extract used, the quality, color and flavor of your beer will vary wildly. Hopefully you can find one you like. Adding some steeped grains may help hide the cidery flavors also.