Cracking little cars but dont really have the tuning potential of an ST focus, so it depends what you are after.
Most reliability problems are caused by thrashing and a lack of maintainance, althoguh they arent exactly Audis for build quality either realistically.
Go and test drive one and make your own mind up mate
Just remember they are the weight of a 3 door nearly, and a little less power, so basically performance is the same as a standard 3 door, ie not good if you are used to modified turbo cars like most of them people on this forum.
So dont expect it to go like a 200bhp 800kg nova does!
To the normal man in the street though they are a little rocket ship.
Need a diff really though, same as the ST does!