The Omen series is expanding with GTX 1060/1070 options for notebooks and 1080 options for the Omen X desktop. New SteelSeries accessories are coming as well with availability beginning this September.
http://www.notebookcheck.net/HP-updates-Omen-17-notebook-with-GTX-1060-1070-graphics.171901.0.html
The hp omen 17-w151nr pdf sheet shows that it has a 15.6 inch dispaly(at the features part and the spec sheet part) so it looks like it has a 15.6 inch display . :)
Ali you seem to be right about that. However, the 17-W104 and 17-W101 are both 17" with 1080 and 1060 respectively I believe.