Rubens is the only one, then, with true front-team experience at Ferrari, then Sato at BAR, while Bourdais only ran with a midfield team andthe others are either less experienced or just rookies.
Sato ran for BAR when he still didn't reach his peak, but his 2007 and the bits of 2008 driving he managed to squeeze in were obviously a lot more mature. The RTL commentators were scared to death when he passed Alonso at Canada - they were pretty much 100% sure there's going to be a crash, and judging by his reputation, in an earlier year this indeed would've been the case. Sato always had the "balls", it just took him a while to tame himself.