If you want an automatic, the DSG is a sweet one--definitely not a "slush-box." Plus, it can be made even sweeter with a DSG tune. That said, tuned or not, it's not quite as awesome as Porsche's PDK.
But if you get so much joy from rowing your own gears that any automatic just won't cut it for you, then go for the manual gearbox. Just know that the nice, soft, clutch that VW puts in the R can just handle the power that it makes stock, so if you plan on tuning it, or even just doing many hard launches, you'll need to upgrade the clutch, which also means that your left leg will be getting more of a workout whenever you drive.