Those with Experience: Knitting vs Crochet?

Hello, I'm an experienced crocheter specializing in amigurumi. I tried to learn how to knit a few years back and could not understand it. To those of you that are able to do both, which do you find easier: knitting or crochet? Also, do you cast on knitting needles the way you would do so with a crochet hook? Also, do you lefty knitters have much difficulty?