Scattering is my favorite too. I haven't heard all of The Incurable Tragedy (their fourth album) yet, but I like what I've heard. I'd agree that it's a step down from Scattering, though. They haven't released any albums past The Incurable Tragedy yet, but they have released a couple of songs.
The first was "Sandstorm" which they did two versions of, one with Stu on vocals, and the other with Tim Roth (the guitarist). They were both good, but I actually preferred Tim's version.
The other one was called "Fukushima" and to be honest, I don't like it at all.
On the singer front, I think what is happening is this: Stu is still in the band, and will sing on studio releases, but can't play live because of Iced Earth. Amanda Kiernan is their new live singer, but she will sing on the studio albums as well, making Into Eternity effectively something like a five-vocalist band.