Re: wondering about the TDI.... (freestyle)
Reliability? Not too many issues. Certainly not oil consumption (that's a 2.0 problem which doesn't aftect the TDI).
MAF sensor is a problem on all Mk4 VW's, not just TDI, so it doesn't matter which engine you have from that point of view.
Timing belt has to be changed every 120,000 km / 80,000 miles, the change interval is not much diferent from anything else out there that has a timing belt, and the job is every bit as miserable on a TDI as it is on any other Mk4 with ANY 4-cylinder engine gas or diesel.
Fuel filter has to be changed periodically, and it costs a few bucks, but it's easy to do yourself. (5 minute job.) On the plus side, NO oxygen sensors, NO sparkplugs, NO ignition coil packs or plug wires. EGR sometimes makes the intake manifolds clog up but it's easily preventable. And you have
http://www.tdiclub.com as a resource.
I'm at 248,000 km and have had zero engine related issues.