another comparison you might be interested in is the difference between the "GTX" 260m and the "GTS" 260m
Most buyers focus mainly on the number and not the specs between gtx and gts.
Short answer is you cannot go wrong with either card...but, the GTX version has more cuda cores 112vs 96
increased giga flops 462vs 396
but is lacking in raw memory clock speed(MHz) 1375 vs 2000 and memory interface width of 128bit vs 256bit
they both do dx 10.1 and open gl 2.1 with a maximum resolution of 2048x1536 digital and vga with exact same connector ports.
Basically the GTS is a factory overclocked gtx and wont make a bit of difference for most users, however you might take that into consideration when comparing laptop prices "bang for the buck".
Often times different manufactures use overlooked specs like similar video cards, smaller or slower hard drives, CPU's that may look better (i7q vs i5), but often have a slower clock speed even if they have more cores; in an effort to make their product more appealing for a lower price, even if certain parts have been downgraded to do so.