Hi, I have just fitted a similar unit in a customers house. It was not as expensive but neither as handsome as the one you link to being honest. Everyone in the house and visitors to the job seem to like it and it works well. The plumbing is pretty tricky. Firstly there is the obvious problem of planning then actually working with all the plumbing in a confined space and like all flush fitting toilets, fitting the toilet connector is a frustrating process. Secondly the toilet is set in a fixed position that is set by the design so you may get lucky or you may have to adjust your existing waste pipe position, use a bit of trial and error with pan connectors, test the imagination of your plumber or a combination of the above.
In summary the look good, they are practical but depending on your existing layout can be difficult to plumb. But as I say to my customers, plan your kitchen or bathroom to get what you want from it not to make life easy for those working on it.