Only 1900 miles to date. During the 1st 1800 I used the transmission in the regular Drive mode, and seldom switched to Tiptronic. Fuel consumption was slightly better than 19/28 EPA estimates, the 1800 mile average being 26.7 mpg. I topped up the tank at 1800 miles, then started using Sport mode. Only 100 miles in Sport so far, but doesn't seem to be the fuel sucking experience that the salesman made it out to be. I'll try this for another 1700 miles so that I can draw a fair comparison between Drive and Sport. Using the Tiptronic just seems like too much work - for everyday driving that is. Perhaps it's intended more for off-roading.
If anybody's interested, my 2006 E-class had a two mode tranny; Comfort and Standard. I'm getting the impression that MB Comfort equates to VW Drive, and MB Standard equates to VW Sport. I didn't care for the "mushy" feel of MB Comfort, it delayed lockup times between gears and actually locked out 1st gear when less than half throttle was applied. So I spent most of my time in Standard, preferring to actually feel the driving experience. I reserved Comfort almost exclusively for slippery road conditions when starting out in 2nd gear induced less wheel slippage. Given the E-class experience, I have a feeling - assuming negligible fuel consumption differences - that I may end up using VW Sport as my preferred mode.
//greg//