Been enjoying the ST for 2.5 years now, no real problems at all. Regular servicing is important as it is with any car. I do the oil every 6k myself or the local garage who charge £40 then a full service every 12k at Profile automotive in Stockport who are excellent and very well recommended by the owners club.
Car has done 75K now, running completely standard, no mods at all. 18 months ago I attended a RR at Northalerton with the Yorkshire STOC group and got 245 BHP on super unleaded when it had about 60K on it. A guy with a brand new ST with 9K only got 230 BHP so make of that what you will.
People think the fuel usage is pretty bad but it depends what you are used to. Ours is the only car so we do about 18K a year maybe more and average 25 MPG Mostly dual carrigeways and North Yorkshire B roads
The buyers guide in the back of Evo this month is spot on.