In this demonstration, conducted by the same source as the original testing, we see the PS3 Slim (firmware 2.8) load Uncharted: Drake's Fortune against the PS3 Slim (firmware 3.0). The difference is considerable (you know, for adjustments to software alone), and we don't see why most other games wouldn't encounter similar loading improvements.
Of course, whether or not the Slim is booting or loading Blu-ray movies with less delay than before is yet unmeasured (so you may have gravy without the meat and potatoes). But given that the most annoying wait times revolve around game load times, let's just call the Slim the overall winner and be done with it (well, technically gravy
can't shouldn't be the most vital part of any meal, so maybe this metaphor isn't working out). [Thanks Eric!]
UPDATE: Blu-ray loading is faster, too.