I have had 6 VWs and have never had an electrical issue, unless you count the bad insulation on my 1971 Superbeetle that caused a short in my ignition back in 1983. I have had very few issues, non electrical and none that you could attribute to something other than normal wear and tear. I had to replace wheel bearing on my Jetta at 140,000, oh, and I had a syncro replaced under warranty at 99,000 miles.
All cars were high mileage. My last one was a 1995 Jetta with the 2.0 gas engine. I had 189,000 trouble free miles on it. The body looked great, interior looked great and the engine had good compression on all cylinders. I changed the oil at around 5,000 miles though sometimes I went over that. The car consistently got 34 MPG on the highway and 28 in town. I would have kept it had some idiot not have rear ended me. I decided to move to something else instead of fixing it. I still got $3600 out of it as it was.
I would not hesitate to get the TDI, it is a great engine. The only reason I don't have one is that I have reached a point that I don't really want to pay $25,000+ for a car anymore. I have gone back to basics. If I were to buy a car for that much money or more, I would want an engine that would last, and the TDI can.