although i didn't own any of those headphones you mentioned above, i own(ed) similar iems and can give you some idea.
xb60ex: i got xb30ex. xb60ex is one level up than xb30ex in this series. xb90ex is the flagship. xb30ex and xb60ex has same driver. they're supposed to sound similar i believe. xb30ex has a lot of bass which veils the mids and highs are recessed. the bass is kinda muddy, although goes very low. burn-in and some equalisation tweaks make these sound great though. i think xb60ex would be less muddy and cleaner sounding than xb30ex. the large drivers and size gives big soundstage for price.
xb60ex would give best details among the 3 u mentioned, with eq tweaking, treble will improve well.
ex210: i had ex300. these look same. ex300 is a better model and meant to sound better. but they should sound similar. ex300 is warm, sweet and detailed with great bass extension (slightly mid bass bloat). every genre sounds good. metal as well. ex210 would sound bit worse i think.
cx300: i had cx300-ii. these dont have 13.5 mm driver that sonys have, so smaller soundstage and details. but the sound is yet balanced and whatever u hear, u hear clearly. bass is perfect, low and enjoyable.
i suggest the xb60ex.