Over the past 30 years of owning cars, I have had manuals and automatics. The 09 JSW TDI has been my first DSG. I've put over 20k miles on it in mixed driving and quite frankly am glad I chose the DSG over the 6M (I test drove both). To me it provides the comfort of an automated shift system with the flexibility of switching into "manual" control - I agree that one could argue that the Tiptronic is not like a real manual, but I like it more actually.
I think of the DSG as a manual tranny mated with a complex algorithm to do the shifting. Since the shift pattern etc. is controlled by software, it cannot be expected to shift in exactly the same way that I (or for that matter any other driver) would. However, that by itself does not make it (IMO) any "better" or "worse" - just "different".
When I first got the car, I tended to drive it like any other automatic transmission but over time I've "learnt" how the transmission shifts/reacts in response to my foot pressure on the throttle, car speed, load, etc. I have instinctively adapted my style to the heuristics built into the software and find that I have all the necessary control required to shift as I want - I don't even think about it now. I just reach over with my hand to switch between D, S and +/-, and my foot on the throttle works in tandem. The absence of a clutch pedal just means that I do not need to use my left leg. When I first drove the DSG, I could never have guessed that I would need to adapt my driving ... but now it feels natural to me ... and it all happened within the first couple of thousand miles or so without my having to consciously think about it - as the operator of a complex piece of machinery, I have just adapted my style over time.
The DSG is a complex piece of machinery and in my opinion to get maximum benefit/fun out of it, you need to learn how to work it. This explains why I thought it was just a ho-hum thing at the start (but I still chose it for other reasons) and possibly why some who drive it for the first time are not impressed. For one it cannot be compared to a standard "automatic" since it is intrinsically has manual gears which feel quite different from a fluid coupled automatic - that may put off those expecting the "smooth" (and for many of us, "lifeless") feel that the standard automatic offers. Second it has its own idiosyncrasies in its shift pattern and this can be irritating to those used to full control on the shift pattern. Drive it like you would an automatic (i.e. without "thinking") and at times you may feel like you are sitting in a manual transmission car driven by someone who does not know how to shift well - it can be made to shift in a "jerky" manner.
However, spend some effort learning how it reacts and adapting yourself to it and it can offer (IMO) the best of both worlds - the comfort of an automatic and the fun/control of a manual. At least it does for me.
The cost issue is a very different matter and opinions can be even more subjective. For me it was obviously worth it to get the DSG inspite of the cost differentials I had projected. For some it may not.