UbloxM8P vs Skytraq px1120r

I am familiar with M8P performance,I want to try PX1120r because of cost but cannot compromise with the performance.As i go with the documentation of PX1120r it seems pretty god but want to know what are the practical outcome after testing PX1120r.Most of my Focus is on Position and Height Accuracy,also attaining maintaining RTK FIX.If any issues that i can Face kindly mention.
thank you.