I have not compared them. I did however have a Firehawk G3 for the last 5 years ( up until recently ), and it is a very good screen surface. In a room that isn't highly light controlled, it produced a nice looking picture!
I have already ordered Firehawk SST. I hope I will be satisfied :-) My first option was ST130, however I have light colored walls and ceiling and it washed out easil even with lights out (due to reflections).