Jetta TDI reliability

I'm thinking of getting a used Jetta TDI. How reliable are these cars generally? The ones in my price range are pushing 100k miles. I've heard that diesels can last well beyond that, but how much farther can it be expected to last with good attention to maintenance, and what (if any) major work should I expect to have to do with such high mileage? For example my Jimmy recently hit about 100k miles (I've had it since new) and I've had to do spark plugs and various fluid changes, etc. Also, someone kept saying that Turbo Diesels require more maintenance than a standard unleaded fuel driven car. Is this true? If so is it significant cost-wise? Thanks in advance for any info you can provide.