yeah the pd engine is a nice unit however does sound alot like a tractor.
I still rate the PD engines. The early 115bhp was not very impressive at all, the even earlier 110bhp TDi was smoother and quieter, if not quite as lively.
VW has subsequently abandoned the PD system in favour of common rail injection. It's questionable as to whether this was a good move - I suspect it was to do with ever tightening emission control legislation.
Whenever you mention the HDi units everyone thinks of the 2.0 90 and 110 bhp engines.
The 2.2 HDi16 is a very different beast. Some would say ahead of its time. Possibly it was.