Yes - it is faster than my CLS 350CDI was and it is more agile. The acceleration from say 50mph is very impressive. In my opinion if you are buying one as a tax efficient car that is also very rapid then you will be very pleased but if you are buying it for fuel economy only then you should have bought another car. My diesel CLS used to average about 50mpg on a 150 mile regular journey and driving in the same way (cameras and variable speed limits) the C350e does about 45mpg. I went for a C350e for a number of reasons not least that even back in March when I ordered it, I thought diesel residuals would melt.
There has been some exchanges on here about companies incurring greater cost due to the consumption of the C350e over say Audi diesels - this ignores the fact that as the emission is only 50 then the company can offset the whole purchase cost against corporation tax in the first year so on a £ 35k car they offset at least £ 7k or all of the lease cost. Cars above 75k/km receive only partial tax relief. £7k buys a lot of petrol !