The biggest difference between the two isn't going to be in their specs, but in their form factor. Assuming that you compare the 17.3" GL702 with the G752, you are going to find that the GL702 is thinner, lighter, more portable, but also hotter. The G752 will be thicker, heavier, and less portable, but it should perform better themally. If you want lower temperatures that the cost of some portability, go with the G752. If you value portability more than thermal performance, go with the GL702.
Here are some results from a site that reviewed both a G752 and a GL702 model.
*Daily Use – 1080p Youtube clip in EDGE for 30 minutes
*Load – playing Need for Speed Most Wanted for 30 minutes