Just Drifting: I started out looking at 1.8T's, looking at Golf pocket-rockets. I hadn't considered a TDI, but it's just different enough to wind me up. Ended up going all the way wacko, and bought a TDI New Beetle (hey, you going to be different, be really different, you know?).
I lurked in these forums for over three months before I finally realized that I what I wanted was a TDI. And the range of knowledge and experience that you'll find on these forums is immense- it's an added benefit that I don't think exists on any similar forum devoted to any other type of engine technology. The folks out here are passionate, dedicated, knowledgeable, helpful, and have a pretty good sense of humor- the kind of folks you'd enjoy hanging around with just kicking things around a bit.
Beyond a test drive, you'll be very suprised at the how quick off the line the TDI can be (especially with a manual trans). I have a bone stock unit, and have no problem getting out ahead of traffic, nor entering freeways. The next suprise you will have is when you're motoring at 65 MPH or so and find you need to pass some slower traffic- no downshift from 5th gear necessary- all the power is still right there. I'm convinced that a TDI could climb trees.
The power is all in the low RPM's- the torque maxes out around 2000 RPM, unlike the 1.8 which doesn't max until much higher. Once you change your thinking around- and your shift patterns- I think the TDI will meet or exceed your expectations for performance.
Finally, all of that performance is still there- with fuel usage in the mid 40 per gallon range.
If you like to wind out an engine to the redline, and like high RPM driving, buy a 1.8, or a Civic, or Ford Focus, or something. But once you really drive a TDI- and not just a test drive from the dealer, I think you'll be hooked- and you'll be one of us.
Good luck.
-Tapokata