I can only say the VW 1.4 TSi engine was brilliant but have no experience of the newer 1.5 however when the 1.5 engine first appeared there were niggling problems, most seem to be some sort of Kangaroo effect mostly in the Golf but other models too.
This forum and many others forums were full of complaints though if I remember right it did not effect DSG models as much but all that is history now and it would seem the 1.5 has become a little darling like the 1.4, put it this way, I hope to order a Touran with the 1.5 engine in 6 months and have no worries about it.