There are a few things to be understood here before concluding anything.
(1) Luke wrote his Gospel in Greek, conveying the original Hebrew or Aramaic by means of equivalent Greek — linguistically or doctrinally. He did not write in Hebrew or Aramaic, but he did invoke Old Testament imagery and parallels throughout his Gospel in order to connect in the readers mind the dots between Old Testament types and their New Testament fulfillments.
(2) There exists no single one-word parallel to the word "Kecharitomene" in Hebrew or Aramaic. As such, this word must be considered to approximate a Hebrew or Aramaic original. St. Jerome seems to suggest that the original Semitic was "full of grace." Indeed, the Semtiic New Testaments, including the Syriac, thus convey this verse. (In a Semitic culture and language, "full" of grace would simpy confess the perfection of the favor of God, not a fullness as in a liquid absolutely filling a vessel, although this metaphor is quite apt.) See Luke 1:30: "Thou hast found favor with God" (i.e. clearly this is meant in a greater way than others, since Mary was favored enough to bear "God With us").
(3) The closest possible equivalent in Hebrew of the name κεχαριτωμενη is the Hebrew name Hannah (Graced/Favored), which would directly translate to κεχαριτομενη in Greek. I find this particularly significant, since Luke attempts to draw parallels between Mary and Old Testament figures elsehwere in his Gospel,a nd quite overtly (the most obvious example being between Mary and the Ark of the Covenant; cf. 2 Samuel 6; Luke 1). Hannah, of course, was the woman who begged God to concieve a son despite being barren — an obvious parallel to Mary who would loved to have conceived the Messiah, as a daughter of David, but asked, "How shall this be, since I know not man?" Their Canticles are also very similar and comparable.
(4) To use κεχαριτωμενη in the way Luke did (or rather whatever equivalent used by the angel Gabriel was used), implies that it was used as a kind of appelation or title, replacing Mary's name with what God viewed her as — her fundamental identity in the eyes of God. In other words, when you use 'blessed among women' as a superlative, you aren't just saying 'you, like countlesss thousands of others of your sex, are blessed,' but rather (since Hebrew has no 'superlative' forms of words, 'the most blessed of all women,' similarly, when you give Mary the appelation or 'name' or 'title' 'κεχαριτωμενη' you are calling her the most graced of all women, 'the markedly graced one.'
With these facts in mind, both translations are correct.