Well i have a zeta 2, which is almost identical to a zeta 3, and the biggest difference i found was that the shoulders are very comfortable. I sat in other bride, a gtr seat and a sparco sprint, and their shoulder's were just not right, for me anyway. The zeta is also tight on the hips whcih is great, but really good on the shoulders. I'm 5'11, 82kg's with around 56cm shoulder width.
I also have a quick release kit, which makes getitn in and out ALOT easier.