Not really - benchmarks as well as other indicators (pixed fill rate, bandwidth, etc.) show them to be behind top-end NVIDIA mobile cards. 4xxx series might correct that, but hopefully it won't turn into vaporware. Remember that the 3850/3870 have been released many months ago, but they were basically vaporware until a couple of weeks ago - no laptops were available that had them. Even now, only very few laptops have them. Given that, who knows how long it will take for the 48xx series to actually appear in notebooks. Hopefully, it will be faster than the 38xx series.
What top-end cards? The 9800m gtx et al? Sure! 9600m GT or less? Certainly not However, all of the higher end mobile graphics cards are actually not good for the whole notebook-idea of portability etc., as they simply use so much power they can't run at full speed for very long when the notebook isn't connected to a wall socket... So yes, they aren't widely used.