Originally Posted by Hempy
...The Typhoon, however, is a proven aircraft. The F-35, by anyones standards, has proven nothing. Therein lies the difference...
I think people are just pointing out how long and how much more money it has taken since the first Typhoon flight in Mar 1994. Typhoon didn't assume responsibility for UK QRA until Jun 2007 (13 years later) and wasn't formally declared an advanced AD platform until Jan 2008 (14 years later).
Although the first F-35A flight was in Dec 2006, the first F-35B flight wasn't until Jun 2008.