I know this post is old; however I came across it today and I thought I would add my own input. I do not own a Prius so I can not speak directly for their reliability. But I do/have own/ed VW's. A 1980 Rabbit, 1989 Fox, 1996 Jetta and now a 2011 Jetta TDI wagon. All previous vehicles were retired with well over 200K miles. They've all been 4cyl/ 5spd cars. The '80 and '89 had no power accessories. The '96 is well optioned, with some of the electronic components beginning to fail (The car has 230K miles on it now) The build and interior quality of all the cars is /was excellent. The exterior finishes were never any good. (They've all be gray, and the '96 has been repainted once). When I went to replace the '96 I looked and a hybrid Lexus and Nissan Altima, among others.The Nissan was larger than the Lexus and cheaper so I rented one for 3 weeks to get a feel for it. I was rather disappointed with the performance and fuel economy. The Nissan averaged 29 mpg over 2200 miles, with 1/2 of that coming from a long trip, the other day to day driving. As a comparison my '96 averages 34mpg I also have a '60 Rambler station wagon with a 6cyl, 3spd and overdrive that averages 30 mpg on long trips.
My TDI has averaged 42 MPG with mostly around town driving. (I've only had it for a few weeks). Given my experience with VW's and the relative conventional nature of the drive train, I bought another VW. I hope this information proves useful.