As far as I am concerned - the biggest downside to the DSG is cost. First, it costs more to buy. Second it costs a lot more to keep it working. The DSG requires a fluid change every 40,000 miles. This fluid change requires special tools and VCDS and the cost varies between $250 to $600 depending on who does it (it's a little cheaper if you do it yourself). If you put a lot of miles on your car this could be an annual expense.
As for reliability, the DSG usually appears to be pretty reliable, if it gets the required service. The manual transmission is very reliable, but the ECU/clutch (stalling) issue does take some getting used to. In the end, it's your choice - do you want to be in control of what gear you are in, or do you want a computer to have that job. In other words, do you want to shift gears, or do you want it to be automatic. If you want automatic, you have to pay the price.
2009 Jetta SportWagen TDI
Candy White/Anthracite; Build date: 01/16/09; Buy date: 02/09/09
Coveted Three Pedal Version, Big hole in roof
Dieselgeek Shortshifter & Panzer Plate (my favorite & my smartest mods)
2MicronTech Pure Flow and Contain Flow CR fuel system modifications