Ours is 3 yrs old in April, now done around 21,000 miles.
Much of it short journeys (5ish miles) to/from work by SWMBO but a couple of times a week 10ish mile journeys. Haven't had any dpf issues.
Obviously have longer runs too, but the above is a normal week.
It's been in the workshop twice so far - both normal services.
Wheels very prone to kerbing, and with the kerbing we have also cut the side walls of 3 tyres. New tyres £125 front, £175 rear
Having said that, they've all been on nearside. The offsides are still OK after 21k miles.
Ours has audio 20 and Becker sat nav. Becker is ok.
Heated seats a must and parktronic useful.
Sport mode on the gear box is a hoot - I've unintentionally hung the back end out a couple of times. Handling is quite tight for an open top car.
We're changing cos the lease is coming to the end and it isn't worth the option to buy payment. We "need" a bigger car (hence the E-Cab) for occasional rear seat use. The E-Cab is no where near as sharp as the SLK
One or two little surprises on purchase (corners cut in our opinion):-
flimsy sun visors
no auto wipers
no auto setting on climate control.
Bottom line for any car - yes, we would have another