Purely based on price, you should be comparing the ES18 with PL13 and the JVC Marshmallows (HAFX34) at around the 500/- range, and the PL21 with the PL11, Creative EP630 and JVC Marshmallows (HAFX35) at just below 1k range..
I'm using the ES18 right now, and it does have good bass compared to...