The most annoying was the jerking of transmission when changing 1st to 2nd gear. It was there when I bought the car, and last owner insisted it was there from the beginning! However, during the time I have owned the car, it went worse. Sold it to avoid major transmission repair.
Ball joint went bad and had to replace at 92000miles.
Idle speed control motor went bad and had to replace at 95000miles.
Having check engine light for coolant sensor. Coolant was going low. There were no visible leak, however.
The most difficult thing of owning a Mitsubishi is to get replacement parts. Dealer parts are very expensive and there is no dealer in Ottawa, Ontario, Canada (Yes, that's true!!! The nearest one is in Hull, QC. Another one is in Kanata, but the one in Orleans closed recently!) Mitsubishi Canada should really focus on this issue as I think this is the most annoying when you run an old car with so rare parts.
The problem with transmission might be the lack of maintenance of last owner.
Why are you giving it such a good rating then?