One purchased for my daughter and one for me (I liked hers so much I bought one for myself,) her Catera has been some trouble.
In 40K miles, A/C hose replaced (I found one used on the internet), alternator replaced (mine too) with a used one for $80, no trouble since. I changed the light bulbs in the dash (so easy... really 5 minutes; try that on your Mercedes), a crankshaft position sensor ($180) and $80 for the key when she lost it. Both cars leaked oil and destroyed the coil modules at about $600 per car.
Mine had a coolant leak costing about $250. Bottom line is about $1600 for 80k miles total. That puts my cost per mile at about a dime a mile if you include reasonable depreciation, which is cheap by any measure.
Some things don't get fixed; her interior lights and my load leveling shocks in the rear. I am not happy, but I am not sad either.
I would never buy another Cadillac of course, and add to that I would never buy another GM car either. -Alan K. Wells