So far, love this thing.  It's mesh.  Haven't had the chance to run it in dusty conditions.  Will have to report back on that.  We rode the Black Hills in SD last week and it was chilly.  I think it's going to be great when it's hot, especially with the half windshield.  Air should flow on through.

Had a good long, hot gravel road ride yesterday.  This rear window thing is pretty cool.  I run the half windshield.  I was the second in line, and got my fair share of dust.  I was dusty, but it's not like it was swirling in the cab.  And I had good air flow.  Haven't had the chance to look at the filter, but the inlet area doesn't show any real signs of excessive dust.  So far, I'd recommend this.