Just to be clear, Nicoticket says that none of their eliquids contain diacetyl, but that certain eliquids do contain acetoin, acetyl propionyl or both. Notices appear to be provided wherever applicable.
Unlike most of the industry and to Nicoticket's credit, Nicoticket is - and as far as I know has always been - quite up-front about it.
That said, many of Nicoticket's eliquids taste very good, IMO. I think I've tried most of them. Personally, I'm now trying to limit my exposure to diketones, but many vapers - probably most - don't seem to care all that much.