The UFX is excellent! (as are all the derivatives)
Exactly what you'd expect (rock-solid and great sound).
Note on USB-3, the latest firmware for the RME units allows them to "work" when connected to USB-3 controllers.
That said, if you're pushing the unit hard at ultra low latency settings, you'll achieve better performance connected to the USB-2 controller that's integrated into the chipset.
ie: If you plan to use the unit at a 48-sample ASIO buffer size, don't connect it to a USB-3 controller.
If you have the budget, the UFX will easily last you a decade.