Those well-versed in Java will quickly come to grips with the QVTo syntax. The tooling of Eclipse QVTo is not quite as comfortable as JDT, e.g. a formatter is missing, but by and large it is quite decent. A real plus, from my point of view, is the meta model explorer, that is independent of QVTo and very useful for working with EMF.
Having worked with QVTo for some time every now and then a bug or feature gap deemed worthy of a bug report:
Currently I am working on the implementation of QvtOperationalResourceImpl.save(). This will finally enable QVTo transformations to create the likes of them.
Actual QVTo transformations I am working on.