I'm a new owner of a Surface Pro 3, i5 w/256Gb SSD & 8Gb RAM.
Started out getting a Yoga 3 Pro. Not a good move!
The Yoga 3 Pro uses an 'M' processor and is very laggy, very easy to have it miss a touch. And no stylus support beyond the sucky capacitive ones! Got it this morning, took it back to BB and got the SP3 and Type Cover. Doing updates on it as I type on my MBPr after getting all my apps and app data in place.