My rule of thumb:
If there are artblades that match the playfield art with no randomly posed characters: I get those art blades. Else I go with mirror blades.
I've even gone so far as to email tiltgraphics on their AIQ artblades and asked them if they could do a set without characters, which they did. Bought them and was very happy with them as they matched the playfield art perfectly. A couple of weeks later tiltgraphics had quit selling the one with the characters...