The misses has hers a couple of years, only two issue, one being the folding mirror motor going and so clicks about 3 or 4 times when they fold in and the other being the mechanism/wire to put the seat forward to get in the back seizing both common issues and both sorted under warranty at the time.

They are a bit heavy on juice for the amount of power you are getting but not horrific.

In general they seem to be a very reliable car with few issues noted. I think if you get a looked after one you wont have to touch it.

Also worth considering the MK6.5 ZS, will be a bit cheaper to run and dare say they is little between them in performance day to day, if anything the ST felt like it should have had more grunt to justify the fuel, and also seems to be as reliable.