His drumming sounds really good on the first Nevermore album to my ears.

?

I don't remember it being anything dramatic, to be honest. I was working with them around that time but believe it wasn't performane related. Maybe Mark just didn't want to commit to the heavy touring they were about to start with the band. You probably know that first album is just the band's first two demos put together, with Mark on the first and Van on the second, so the best songs of each were put together, remastered to make them sound more even, and re-sequenced. The Arrington songs from the first demo that didn't get used on the album later surfaced as B-sides on reissues.

I know Jeff used Mark to record drums for his first solo album, "Zero Order Phase". But then didn't use him on his second record for whatever reason.