"Candlemass" for me, not only because Messiah is my second favourite Candlemass-vocalist after Johan Langquist, but also because of the songs themselves.
I bought "Chapter VI" when it came out, but found it somewhat disappointing, maybe partly also due to the new vocalist, and then sold it a few years later to a penfriend who was interested in it. I'm not familiar with "Dactylis Glomerata" and "From the 13 Sun" - I think the reviews I read about them didn't sound very promising and the disappointment with "Chapter VI" made me refrain from checking them out. I've got the three albums with Robert Lowe on vocals, though, but while there are a few songs I really like a lot - especially "Embracing the Styx" and "Hammer of Doom" -, I like the songs on "Candlemass" better than on any of these three. (I'd also say I like the first two albums by Solitude Aeturnus better than the albums Robert Lowe recorded with Candlemass.)