I think
Aveline is very pretty. I really like it. However, I don't know if I like it enough to use it, mostly because aveline is a word in French (hazelnut). It's not a word I hear every day or anything, but I know some people, namely my grandmother, would think I'm crazy, lol.
As for the name's lack of popularity, where I live at least, names that end in "-ine" are generally nicknames (ex.
Angeline or
Nicoline), so a few people may feel that it seems incomplete or too "nickname-y".
Pronunciation could also be an issue, but it's not like
Ava is fool-proof in that sense either. I do know an
Ava who pronounces it
ah-vah.
Also, just like
Adeline,
Aveline can be pronounced two ways:
av-uh-LEEN or
AV-uh-lien. I greatly prefer
av-uh-LEEN.