Sketch has a lot of potential. It isn't quite there yet for me though, maybe in a few years.

What I don't get is why everyone keeps comparing it to Photoshop. They are completely different from each other with their respective advantages/disadvantages. A comparison with Illustrator or possibly InDesign or Fireworks is much closer with shared advantages as well as disadvantages. No tool is a be all, end all.

Ok... I disagree with pretty much the whole premise of this article. It's like saying that red is the only color you need since it's a good color.

We as digital designers are finally getting to a point where good typography is possible online – we're no longer restricted to just web safe fonts or fonts that render well on very low resolution screens. Yes, this means that we need to become more knowledgable about typography, but in return we gain a far better set of tools for communicating through design.

I'm too a fan of the approach the GDS team is taking. Very thoughtful but at the same time approachable and understandable. The design principles they use are fantastic: https://www.gov.uk/designprinciples

Their blog is often worth reading as well: http://digital.cabinetoffice.gov.uk

I'd say go for the Retina. The whole industry will have to work out how to approach higher resolution screens. I figure that the sooner you get started on trying what works and what doesn't the better. It also more closely mimics the resolution of tablets/smartphones, so designing for those types of devices should be easier.