I haven't read Saito's books, or looked too deeply into degrowth as a movement. I just read this article and thought it made some good arguments against what it claims are Saito's understandings of Marx. I'm not sure I agree with everything, but I thought it was interesting enough to share.
Are they bad?
Meh. Wrote an overrated book about central planning (thesis is that central planning is possible because Walmart and Amazon do it - of course central planning is possible but not for that reason, Phillips kinda misses the point) that spends a chapter devoted to shitting on Stalin.
Well take a gander at his twitter but lets say he's a fellow traveler of LaRouche. More importantly for this though, degrowth is a bit of a bugbear for him. He complains about it constantly so I wouldn't believe he's being honest about his criticism of Saito.
ewww