My fuel economy is grand! I think that the st is very frugal on juice, i'd be averaging mid 30's mpg.
As above they do have some flaws. They all generally have a flat spot around 2000rpm which after a while does become tiresome. I would also say that there is a lot of road noise in the cabin which would make you think a wheel bearing is gone.
I got a 2004 model with FSH and only 33000 miles for less than anything mentioned in the previous posts so hunt around you will find them cheaper.
Bar all the minor niggles they are fantastic to drive and feel very secure on the road.