Here's my informed opinion:
Opera
Interesting demo. Symphonic black metal, fairly straightfoward.
Phormula
Fairly interesting Arcturus-esque post black metal. A lot of guitar wanking and shrieks and some clean vocals and a lot of keyboards. The Greyness Grows Already Old is Ephel Duath's best song, but the rest of the fairly short album is kinda dull.
Rephormula
Combination of Opera and Phormula with bonus remixes. Get this one if you looooooooooove Arcturus, but don't expect to be blown away. I know people that absolutely worship it... it's kind of a mixture of Scholomance and Arcturus.
The Painter's Palette
This is BY FAR the best overall release. Every song is wicked, very technical jazz metalcore fusion. Don't expect the typical metalcore-isms such as a monotone yell and a lot of breakdowns. Instead, expect a lot of screams, very technical almost wanky guitars, bass, and drums, a bit of saxophone, and some clean vocals which are kind of like Maynard meets Jeff Buckley, but not as good as either.