I've used them not very intensively, but even with little use, it is unfortunately easy to see that ComicVine is quite misguided in some regards (specially, information structure), and lacks some useful info (won't get into details here, to not seem too harsh, and because it is not the main topic of this thread).
Obviously, I prefer a worse open database than a better closed one, but I'd prefer a top AND open database, or even better 2 of them

That's why I try to not only criticize but add my two cents to ComicVine, but I'm finding... "obstacles".
On the other side, I reached comicbookDB asking for an open API, but in the meantime I found a very recent ( Sep 02, 2014) forum thread discussing the issue:
comicbookdb.com/forums/viewtopic.php?f=2&t=7991
which literally says "Still no plans on an API.", so I'm afraid we're out of luck