As a long-time Subaru customer, I always appreciated their unparalleled reputation for immaculate engineering, longevity and performance. For a number of years they not only won the WRC and other competitions regularly, but their road-cars also featured at the top of the table in reliability and customer satisfaction surveys.
Even with the emergence of their diesels and that dumb-looking (IMHO) Impreza hatch, the cars still have that sporty edge to their reputations, but they no longer seem to feature at the top of the "well-screwed together" league.
Interestingly, Lexus seem to have replaced Subaru at the pinnacle of the the reliability and customer satisfaction measurements and also have that added luxury in their pedigree.
Neither a 2.5 V6 IS200 nor a 2.0 (single or bi-) turbo-charged Legacy AWD will be the most fuel-efficient of cars, but they will certainly have other rewards for the driver. My own personal choice, if I could get one, would probably be the IS220d Sport.
Lexus or Subaru? Each has their own unique attractions and there's not a lot to choose between them IMHO and they certainly blow the bulk of the "me too" brands into the weeds on all fronts. Good choices - happy shopping.