You asked if it is possible to view HD channels on the Avant.
Although I use a different model, Avant US, I am able to view HD content by selecting the output at 480p from my STB, set top box.
Working for a major MSO (multiple service operator), I do notice a significant difference between digital and HD channels on my Avant.
I'm not a resolution snob, but until recently my coworkers thought the Avant was a much higher resolution.