Very portable (small, light, bus-powered), low latency, ultra-stable audio interface. Ideally for use with laptops (producing on the go) as well as in the studio, hooking up all your gear via ADAT interfaces (available in all price categories). Using e.g. Behringer ADA-8x00's, you could mix (TotalMix) 32 Channels In and 32 Channels out with minimal CPU load for less than a 1000 EUR! Although I would consider upgrading to e.g. Ferrofish or better...
RME is renowed for their excellent drivers and supporting their gear many years after they were released.
Why no 5th star? I'm reserving that for a TB3 version which would even have less latency (note that USB3 would have no benefit over provided USB2) or for an even more compact version with 2/2 I/O + headphone (ideal for travelling producers and DJ's).