I am probably just having bad luck, but for me (and others) the new Editor just will not recognise the style sheet(s) that contain the site styles. I know that it has 'seen' it, because it adopts the 'body' class that is contained in the site sylesheet, but it will not add the styles to the HTMLEditor instance style select list.
A couple of us have spent severat hours on this, trying to make it work.
Apart from that, it seems to be excellent - cool GUI - and I especially like that you can add new (extra, ad hoc) styles (property by property) in the GUI. That is a truly cool feature.
I worked myself up into a bit of a huff over the weekend, because none of the last four products I have bought or upgraded to (HTMLEditor, 2xPowerCMS, PowerGallery, and PowerStore4) are working correctly.
I have a particularly huffy post somewhere about here which details this a bit more - forgive me - I was tired and irritable.
Hopefully - there will be answers in the HTMLEditor GSG for this particular problem, and the light will dawn as my ignorance shines through (as always).
I will post separate temperate posts for my other problems later on.