I have cherry picked Diaclone over the years and I have enough to make me happy. I don't go for everything, and I really like the smaller sets that include Dianauts and maybe a few vehicles. It's very fun world building and goes together really well with modern Transformers (for dios and such). I see that he's $409 through TF Source (the only stateside place I currently see it offered). HLJ shows about $270 but I'm not sure what shipping would be, or how that company is.
At the end of the day, this is a cool curiosity that, were it easier to obtain, I would be all over at the $200 mark. Double that though is where they lose me.