Since this thread is eight years old, some of the original queries are largely out of date as the features they were asking for have been added.

The Gregorian chant issue remains, but it is possible to hide barlines. Either select the barline, right click, select properties and go to the visibility tab. From the drop down menu labelled "show on the printed page", select "Never" then OK. The barlines will show in grey on the screen but will not print.

Also Noteworthy, unlike some notation processors, including some very expensive ones, allows you to put barlines where you want, so if you are notating music where barlines are not appropriate in the finished text you can position the barlines so that you can avoid tied notes over them which often happens in modern editions of renaissance music where bar lines have been added according to current conventions.

The long single line on the screen is something you get used to. FWIW, I think it makes it easier to manage music involving multiple parts because the lack of line breaks makes it easier to follow the flow of the music when you are inputting or editing. It only takes a few moments to check the music using print preview to see how it will look when printed.