Its still worth the performance boost from gt650m/gtx660m to GT750m=gtx670m and gt750m sli close to gtx675mx. 
Get new dress with next generation maxwell gpu next year. 

Best is to check and test the display unit yourself to determine the screen quality  . You can also check with the Y500 sifus for feedback over here: http://forum.lowyat.net/topic/2619081

According to notebookcheck, Y500/GT650m sli provides a decent battery capacity of 72 Wh or 6700mAh. It will last around 3hr 10min for surfing and around 4hrs when idle. The battery life is only average.
Its still worth for me to sacrifice some of its battery life to get the sli option and boost the performance close to GTX670mx with the attractive pricing  The upcoming new Y500/GT750m sli is expected to perform close to gtx675mx, is hard to resist around RRP 3.8k(my guess). 
Perhaps, we can also disable the cpu/gpu boost to get more battery juice. 

GX60 CPU is very preppy compare with Intel, it will bottleneck the 7970M GPU and get low fps when playing with high/ultra high resolution in certain games.

Of course you can beat the likes of Y400/Y500..

Look at those spec..

What game u comparing it with? CPU bounded game like SC2, Skyrim, etcs will certainly bottleneck that HD7970M. 

But a bottleneck HD7970M is still better than a GTX60M imo.

GX60 under 4k?

Depending on games.

Notebookcheck did a test.

Average results from 14 games :

[attachmentid=3403354]

http://www.notebookcheck.net/Review-MSI-GX...ok.86283.0.html

The notebookcheck benchmark had two flaw:
-benchmark inc resolution 1366x768
-drivers: AMD driver sux but since GX60 there are alot of drivers update that gain performance due to enduro fix (which cause the GPU not to run at 100%). For the benchmark which driver was used?