I've only owned a 2008 Mondeo, for 3 and a bit years and 37,000 miles.

My owner's experiences are here, the first on the list (at the bottom): http://www.honestjohn.co.uk/carbycar/ford/mondeo-iv-2007/?section=owners-reviews

In brief, it's an excellent car. Big but it shrinks around you when you're driving.

I haven't driven a Superb but I had the 2.0 CR engine in my last Octavia vRS. It's a lot quieter than the old PD unit, and a bit quieter than the Mondeo and C-Max diesels that I test-drove. It's an excellent engine with seamless power delivery from low revs and minimal turbo lag.

Both are very good cars: you need to get a good long test-drive in each and see which you prefer. If there's anything in it, the Superb may suit a more relaxed style of driving and the Mondeo be preferred by the press-on driver who likes to use high revs and reevels in the sharp, direct steeering that Fords are good at. Rather like a choice between Audi and BMW.