I have absolutely no complaints with my 13" both OS X & Windows have positive & negative regarding HiDPI displays. The 13" rMBP is by far Apple`s most balanced portable and offers the best value for money, given it`s specifications. I have to admit that as much as I like the SP4, going back to a limited battery life is not where I want to be.
"Murphy`s Law" always applies, when you need to recharge the most, there is never an outlet available I am now at a point where I want a minimum of 8 hours, if not the trade off needs to be tangible & beneficial on several levels to make this compromise.
Q-6
As far as high res screens goes I have no issues with 1080p with Windows. I found some apps on the surface pro to be a to small. Wasn't a deal breaker though and wasn't terrible. What was the deal breaker for me was the battery life and the amount of ram Web browsing took for just one tab. Guess I am just used to 8gb of ram with my main windows laptop. I also don't feel like I want to purposely gimp the device to get the best battery life out of the device. On Windows central they suggested I should limit the cpu to 50%. Yes these are very good suggestions and I agree I should do that but I don't want to limit myself. One of the reasons why I chose a Macbook Pro over the Air is because of the better screen. Yes the Air probably would of been better for me since I could get a 13 inch Air with a bigger ssd and even better battery life but the 10 suggested hours is fine for me. I've also found myself using the device longer than what Apple has suggested for their devices be it an iPad, iPhone or iPod. If I was rich or won the lottery I would love to get both devices but unfortunately I need to budget and could only choose one lol.