I owned and drove my Buick Riviera from 1996 thru 2004 and never had any major problems from it whatsoever. My complaints would be 3. After 3 years of owning it, the front hood paint began to peel/rust and though it should have been under warranty, GM wouldn't do anything about it. 2nd thing was the heated seat quit working after 2nd winter, it was $500 to repair so I didn't fix it. 3rd thing was the CD player had a problem. Those 3 things aside, I only had to do the regular maintenance (tuning, belt changes, oil, etc.) and I drove it 164000 miles and believe I could still drive it another 100000 but moved to city and need smaller car. Awesome car! I would buy another, if it were smaller!
Fast take off, very comfortable, never any problems with it after 8 yrs & 164000 mi. still looks new (except couple of dents), still drives awesome, fast, its a fantastic car! I'm quite sure it will go another 100000 miles without problems! And only about $1000 per year maintenance, if that.
The paint on hood, I've seen a lot of other Riviera's with the same exact problem. The heated seat wasn't used that much, I shouldn't have to pay $500 after 2nd season of use to have it repaired, it just wasn't used that much. And the CD player was OK as if you played one CD per trip.