The Uni's layout was crafted with ergonomics as a priority. In this article, I'll cover what makes the Uni layout so great, and how it stands out from other layouts on the market.
One immediately noticeable trait is the enormous spacing between the left, right, and thumb keys.
The space between the left and right is for the shoulders, so that you can sit with your shoulders back and maintain a better posture. Also this design choice allows the microchip and USB port to fit in the center with room to spare.
The space between the bottom row and the middle row is to prevent your thumbs from being too close to the middle row.
In fact, the space between the middle row and the bottom row is the same as the distance between your spacebar and home-row on a normal mechanical keyboard.
Moving on, on a traditional steno machine, the thumbs would be shifted about half a unit inwards. The Uni has the thumb vowels shifted by an entire unit. This is to prevent the thumbs from being directly under the index and middle fingers and in a more natural position.
There are two left S keys that you can customize in the Plover app because the Uni uses the Gemini PR protocol. The four asterisk keys and the two number bar keys can also be customized as well. By default, they are not different from each other. Most people won't need to customize this unless you're making a new theory.
Speaking of the number bar, the number bar is not on the top, but towards the outside of the thumbs. It's completely functional as a normal number bar, the only problem being that it's difficult to invert two digit numbers with Plover theory. People have solved this by inverting two digit numbers by pressing #E on the Uni instead of #EU.
Lastly, the Uni is kept unsymmetrical because having two extra keys to the left of the left S keys makes mis-hitting the extra keys very easy. If a mode switch key was assigned to the extra key, it's way too easy to hit it by accident and switch modes in the middle of typing.
The Uni is a great layout, but by no means is it the best possible layout in the world. Each person has their own preference. But it's safe to say that many people will prefer the comfort offered by the Uni's layout.