i voted damier. i have it and love it. i get compliments on it all the time and i like that it doesn't scream 'LV' (i have my mono for that
) another reason why i love the damier, is as some others mentioned, the epi is very classy and dressy, whereas the damier can be dressed either up or down. it looks great with a suit or a trench coat, but doesn't seem out of place on the days i wear jeans and pumas (which is most days, btw!). i feel that the epi would look out of place with very casual wear.
another plus: the damier is less expensive, so you could spend the difference on say, an accessory!