Despite all the negativity relating to the F-35 program around the place, advances keep getting made all the time, making the naysayers start to look rather foolish in my book...
First is the initial description of BF-1's hover pit testing:
http://www.flightglobal.com/articles/2009/04/23/325579/stovl-f-35-beats-vertical-thrust-target.html
Of interest is that the F-35B demonstrated that it CLEARLY exceeds it's KPP in this regard (key performance parameters) in it's very first trials on the "hover pit", demonstrating 41,100lbs of vertical thrust.
The original requirement was 39,000lbs and the re-baselined limit was 40,550lbs of vertical thrust to offset weight gained during development.
Why this is so important is because the F-35's rather vocal detractors have claimed for some time is that there is no "margin for growth" in the aircraft's design.
Clearly this is a nonsense and the assumptions made about the aircraft on this basis are CLEARLY wrong.
It also shows that the aircraft is capable of exceeding it's KPPs, another critical point it's detractors like to try and target. Speed being one such issue detractors often point to, notwithstanding the VERY minimal issue that a lack of outright, top-end speed IS for anything beside marketing purposes.