Was going through the same dilemma 2 weeks back as well.
2016 MacBook 256GB upgrade processor to 1.3Ghz ($1.9k) vs
2015 MacBook 512GB 1.2Ghz ($1.8k).
As I find the Rose Gold too girly, I decided that I want the Gold MacBook. Only plus point for Rose Gold is that people will know it's the 2016 model. But that is going against the color that I really liked.
After much consideration, I decided to go for the 2016 MacBook as I'm worried about the performance of the Core M processors. I was using a MacBook Pro 15" Retina, so thought
I should at least get the highest end Core M processor. Further, I wasn't able to find the 2015 MacBook in Gold at most retailers. Then I happily went for lunch and chanced upon the last unit of 2015 Macbook 256GB 1.1Ghz at 1.4k. MTL, I quickly bought it, still got some freebies at that price.
In the end, was pleasantly surprised that the speed of the lowest end MacBook was sufficient for my usage. I am using it for Microsoft office, surf net and watch movies. There is no lag, and I don't find it any slower than my MBP or 5k iMac as these activities doesn't require much processing power. Am loving the MacBook more than the other 2 Macs now. I actually like the MacBook keyboard much more than the wobbly keys on my MBP.
So for those of you who are looking to use it for checking emails, surf net and watch movies, any of the MacBooks are more than capable. Anyway, the MacBook is not supposed to be a powerhouse.