Hi Mark, that design does look very sleek. However, please keep in mind -- unless your water is 100% treated so that it is 0% hard, 100% soft (filtered water quality) -- there will be hard water deposits. Think about how you will clean the top, the rail, and all the wheels, slider slots, and mechanisms. Especially when it's so close to the ceiling as shown in your photo.
With a frameless swinging glass door on hinges, there is nothing at the top but glass, and the tricky parts to clean the water deposits are the hinges. :) Think about cleaning. If you don't mind, then this sliding system is nice, too. :)
Also, notice the system in your photo, there is very little room for ventilation -- the gap between the ceiling and the top of the glass is very small -- this means when you take a shower, all the glass will be steamed up. The larger the gap and the better the ventilation system, the less moisture on the glass, which means less cleaning (less squeegee action after each shower.) In addition to the cost, I'm always looking at the design, the functionality, the looks, the quality, the maintenance and _cleaning_. :)
Think about cleaning, and compare the different systems. Good luck. :)