Does anyone know more about this? Is it as significant as we are told here?
Really a gamechanger, or just another competitor?
David
There’s already things like Nkoda, which are a digital library of existing publications, as PDFs. But this looks like it’s their own editions and their own document format - probably based on MusicXML, which is why you can transpose it.
That means it depends entirely on how good their engraving layout is. Some of the examples are a bit ropey, IMO.
It’s not really a competitor to Dorico. (There are already a surprising number of notation apps out there.)
With a name only one letter different from a student essay-writing service (called enotes) it’s going to be hard for search engines to get a grip on it!
The Grauniad piece makes a big deal of transposition, but who (except solo vocalists) really needs transposition for classical music scores? Playing “Mozart’s G minor symphony transposed into A minor” isn’t likely to happen very often.
As ben said, unless you can trace their editions back to the original sources, it’s probably not going to fly as a serious tool either for doing research or for professional performers
Years ago, the Portsmouth Sinfonia (I think it was) played Tschaikovsky’s P.C. No.1 in A minor! 
David
What key did the soloist play it in? 
Weeks to transpose a Chopin Mazurka, traditionally? Maybe a week for a plate engraver, I guess…