I was blown away by Apocalyptica's first album. They made a fan out of me and since then I snatched their latest release at the first chance I could. And the only thing more impressive than their musicianship is that they keep sounding better with each release.
Cult is defintely their best album to date. Furhtermore, this is technically their first album since they do mostly Metallica covers in their earlier releases. With the experience of two records under their belt, the confidence of the studio exec to give them a budget, and the freedom to write their own songs; the Cult sounds bolder than anything Apocalyptica has done. You get the feeling that they're not simply mimicking heavy metal, they're pushing the envelope with just how far cellos and metal mix.
In fact, most of the songs are not very metal-like. You can detect influence of trash metal and classical, but the songs are neither one nor the other.
With that said, Apocalyptica is an acquired taste. It's for people who have fondness for string instruments, heavy bassline, with structured but nevertheless complex progression.
As a sidenote, Apocalyptica's latest album Reflection (apparently only available in Europe) is not as good as Cult. While Reflection is basically a very lound album with cellos blasting like guitars, Cult is more refined as a hybrid of the classical meets metal.