Subaru makes diesels overseas and made a vague commitment to bring one to the states around 2004, but never followed through. I wouldn't hold my breath.@740GLE - since when is Subie building Diesels? Or if you go gas why not a TSI? I understand the TDI preference, but you could stay in the VW family?
If my choice of AWD vehicles came down to a Subaru or a TSI Alltrack, I'd go with the Subaru. Every Subaru has a larger fuel tank than the Golf, except the BRZ which has the same 50L capacity. The Impreza and the Forester both have available manual transmissions. Finally Subaru's AWD system is generally considered to be a better system than the Haldex.
I know that Subarus have head gasket issues, and turbo Surbarus have turbo issues. I've personally witnessed and helped repair a few of them, but these seem to be some of the few issues they suffer. The TSI engine has its share of issues from carbon build-up to PCV valves and timing chain tensioners. Few people are going to take you seriously if you tell them your TSI is going to be more reliable than a Subaru, even if Subaru reliability is not all it's reputed to be.