Personally, I like the Y510 more than the Y500 simply because of the anti-glare matte screen. I absolutely do not like glossy screens. However, the only other difference between the two is the CPU; Haswell vs. Ivy Bridge, and the additional 8GB of mSATA SSD cache. However, those differences do not justify the $200 high price.
The GT 720m is most definitely a typo. It should state GT 750m.