Among many things that attracted me was the ability to handle a high flow, with a nice looking water jet too. My deep soaker tub fills up fast, the water stream looks good and sounds good while doing so. A professional water flow noise, not an ugly sound with high whining overtones.
The tailpiece can run horizontally too, although they don't show that in the literature. I turned it on its back. Perhaps that is obvious, but I needed to have that explained to me. The hole in my floor is not directly underneath the overflow standpipe.
I ran my hot water thru 3/4" kitec Aqua pipe (like 3/4" Pex, but bigger), with no elbows, just to get the highest flow possible. As for vavles, i guess i should have also used the stop valve that you normally see on a shower wall too, as they are truly 3/4" throughout. My Roman Tub filler valves are 1/2" in and out, so i am probably getting less than full flow but still something near the top end of the range nonetheless.
The Chicago Faucet and Geberit companies respond well on the phone and always have the right information. When you talk to another agent on another day about something related or even the same concern, you get the same information.
In fact, the only reason I ever even came across it was that I was buying wall-mount toilets and Geberit sent me an entire catalog of everything. So their being proactive was what brought them the sale. They are courteous, patient and able to help. Totally. They are only 90% there in terms of knowledge about the wall-hung toilet bowl carrier that they sell to other firms that make the bowl; it is not the same as their own proprietray brand.
If I had to recommend a change for a future version, I would put two 3/4" entrances on the device, as one is expected to have high flow up to the device, and that'll be 3/4" diameter piping. In my setup I had to make a mixer with a T and some MPT adapters. Competitive devices (search for "erogazione" in Italian) have two 1/2" entrances. I think this means you don't have to buid your own T mixer either, since the device receives both and does the mixing of hot and cold inside itself.
I even looked at another device, something to do with a solenoid valve, that was designed to retro-fit on any old standard Geberit tub drain and overflow kit. I even saw it in action. But I had a good feeling about the Geberit, so I bought it and it works better, in my opinion.
My wife is also happy, and proud, to have the Geberit Tub Filler. So this is one case where the plumbing makes both parties happy in a renovation. She likes the wall-mount toilets too. So Geberit is a good word in our household.