Used the xline on Friday, it is noticeably heavier then the supreme brushes.
Also it doesn't splay as well as the supreme but does feel good on the glass.
When I first starting using the supreme medium hybrid it felt very springy, but after a week or 2 it softens out slightly and splays better, hoping this brush will do the same.
Not sure if I prefer it over the medium mixed supreme just yet, needs a bit of time to be fully broken in.