This is definitively very similar to previous albums and I agree with some of the comments in that there isn't really any outstanding singers, actually my favorite one on the album is the less known singer Sara Squadrani. However as with every other Ayreon album you can't make a determination on the first listen. After a few listens it really starts to catch on cause there's a ton of music to take in on this album. If you're not a fan of the singers or the lyrics there's a version available that includes cd's with only instrumentals which is great.
With The Theory of Everything, Lucassen has further cemented himself as a force to be reckoned with in the progressive metal and rock scene, but has also given us what may be his most accomplished work yet.
There is nothing new under the sun. Ayreon albums are real good, but the last works sounds very similar. The story is cool but is very boring for an a usual listener of his music. I think the flaw of this record is the choice of singers. No nobody stands out, all are very flat, inclusive chessy some times. Maybe JB tone is particular, but Arjen does not take advantage of his talent. In resume this is for hardcore fans.