Was in a similar boat like you, only I bought the SP3 months ago - have had nothing but hardware issues with it since (yellow banding / overheating / typecover not responding / etc). Ended up returning it and went with the Dell Venue 11 Pro - now THAT is a nice machine. Got the just released Core M version that's fanless, and Dell didn't muck it up like Lenovo with the Yoga 3 Pro. Was $799 from Dell plus $100 for the keyboard off Ebay. If you've ever not happy with the SP3, I'd highly recommend the Venue 11 - best of all, it has a battery in the keyboard and I get 12 hours on max brightness, including heavy browsing/Office/videos.
That being said, I'll have my eye on the SP4 and could see myself buying that when it comes out, as I really enjoyed the 3:2 aspect ratio.
Edit: Also forgot to mention, read your earlier post about the Dell stylus - I had the 002 revision at first, and it was awful, but they've since released a new version (the bottom is black and the top of it is silver), and it works just as good as the SP3 stylus. Main difference is that the nub on it is plastic and doesn't wear down like the SP3 stylus, although it's more audible when you tap on the screen with it.