A scale of light and dark options is nice depending on environment, but personally I almost always favor dark UIs. I'm surprised to hear some folks say they find a light UI better to put the focus on their work, because for me the opposite is true. Generally, my screen is the brightest thing in my environment. I keep a dark gray photo for a background on my desktop, and my monitor and MB bezel are both black. So then if my design is at all lighter than its surroundings, with a dark UI it clearly stands out as the point of emphasis without distraction. Putting a light UI inside of a dark monitor generally creates a strange light inner rectangle surrounding my work, with menus and toolbars the brightest and most distracting element. This is why I find Sketch frustrating. But, when working on light-toned work or when working under different lighting (or for eye issues), I can see a light UI being helpful for some.
A scale of light and dark options is nice depending on environment, but personally I almost always favor dark UIs. I'm surprised to hear some folks say they find a light UI better to put the focus on their work, because for me the opposite is true. Generally, my screen is the brightest thing in my environment. I keep a dark gray photo for a background on my desktop, and my monitor and MB bezel are both black. So then if my design is at all lighter than its surroundings, with a dark UI it clearly stands out as the point of emphasis without distraction. Putting a light UI inside of a dark monitor generally creates a strange light inner rectangle surrounding my work, with menus and toolbars the brightest and most distracting element. This is why I find Sketch frustrating. But, when working on light-toned work or when working under different lighting (or for eye issues), I can see a light UI being helpful for some.