Lemme get something right first. Aquarion is never about serious plots, you don't watch it for the serious plot, you watch it for the silly character interaction and silly attacks.
The best part of Sousei? The silly episodes, which was about 3/4 of the show. Best part of Evol? First half. I hope you get what I'm trying to say here.
Anyway, Logos has a pretty silly premise, not a great plot so far, but it's very interesting, especially with all the links to the words and whatnot.
Art? Sure it ain't good, but it shouldn't be the one factor that deters you from watching it.
no Akino/bless4 so far, but May'n makes it up for that imo. As for the seiyuu, they fit the characters, that's pretty standard.
Characters, this is where Logos shine. they are all weird people with funny aspects to them, and their personality mash well together. The best parts of the episodes is always the interaction, Akira being totally disconnected from the others from his savior obsession, Maia not knowing anything other than her mission, etc. They make good use of their quirks and made their interaction entertaining.
Enjoyment: Refer to Characters.
I personally give it a 9. I like good/entertaining characters, and they gave me the latter, in a silly premise. What more could I ask for?