The best Solitude album, by far, is In the Darkest Hour. Second best is Beyond the Crimson Horizon, also a tremendous album.
They lost none of their darkness or heaviness on Adagio--I have no idea how that rumor crept up. It's as doomy and insane as anything they've done, and it brings back the production polish that Downfall lacked.
I'd love to hear a new one from them. I talk to John Perez occasionally and this thing has been "in progress" forever!
The best doom band in metal--hands down--truly underrated.