Uncharted 2 pretty much killed any hopes of Borderlands having a strong launch on the PS3.
I see Inferno ending up in the exact same boat compared to the Xbox version since PS3 owners will all be buying GoWIII instead.
The only reason I picked up Borderlands for the PS3 a couple weeks back (which was in the shrink wrap until this weekend) was that it was on sale at the time even though I had no intention of immediately playing it (Uncharted 2 and Modern Warfare 2).