So let me preface this by saying that I didn't get to take this car on a nice long test drive like I did with the '93 STS and '99 ETC, so my review won't be as long.
Exterior Design: 8.5/10
The Rivieras are a very handsome car, but it looks kind of odd when viewed from certain angles. Overall though, I like it, maybe as much as the 1993-96 Mark VIII, but more than the '97-98 VIII and not as much as the 1992-02 Eldorados.
Interior Design: 8.5/10
The interior is pretty snug and cozy...like the '99 ETC, but the Riviera's interior is much more rounded and everything flows together very well. It's snug and cozy, but not cramped at all. There is plenty head and legroom for everyone on board. I didn't think that there is enough woodgrain trim, but once inside, it doesn't matter as much because you're enveloped in the warm comfortable snugness of the cabin.
Seats: 9.5/10
In the 1995 Riviera brochure, Buick claimed they spent over 80,000 miles on the road, testing different designs for the seats. I say it was time and money well spent. These seats were more comfortable than the seats in the '99 ETC or '93 STS I drove. They were cushier than the seats in my '92 deVille, yet very very supportive. It was the best of both worlds. I don't recall them having more lateral support than the '93 STS, but still they were amazing seats indeed. And for a coupe, there was plenty of legroom in the rear, never felt cramped in the car.
Engine: 9/10
I didn't get to open the L67 up very much, but I could tell there is a ton of low end torque (more than my 4.9 perhaps) and it's far smoother than the 4.9. I did go about 1/3 from about 10 mph, and it pulled far better than either Northstar or my 4.9, it feels a lot more powerful than "only" 240hp...around town it made much more power than the Northstar. Sadly, I never got to open it up or take it above 60 mph, but it got to speed silently, smoothly and easily. Now I'm sure that an L37 Northstar Eldorado would beat this L67 Riviera to 100 by about one second..both are much quicker than my 4.9 at highway speeds.
Transmission: 9/10
The 4T65-E is just like all other GM trannys. Awesome.
Steering: 8.5/10
The Riv's steering was nicely weighted..not too light, not too firm. Firmer than my deVille, but lighter than the '93 STS. Offered good road feel and always felt capable, which brings me to my next point.
Suspension: 9/10
Buick's engineers did a terrific job on these. They feel just as composed and solid at speed as the STS and ETC do, but they don't need the electronic struts to do it. They're very smooth, but not boaty at all, composed and solid, but not bumpy and jarring. A very comfortable and confident car to be driving.
Electronic goodies: 8/10
These Riv's, for whatever reason, don't have all the electronic gizmos that the Cadillacs and other Buicks have, but this isn't all bad. The lack of these makes the car feel like more of a "driver's car", in other words, "ya don't need all the toys to make driving fun" . They've got the guages for tach, speedo, fuel and temp and that's really all you need. It's got Buick's excellently designed electronic climate control, but the display wasn't working on this one, but he was gonna fix it. I didn't get to listen to the radio, but Buick's always have great sound systems.
Overall: 88/100
These Rivieras are a great car. Awesome interior and exterior design, loaded with features, plush, comfortable, fun to drive, composed, confident and cool. Sure, they may not be as awesome as a '93 STS, but it's a lot cheaper to buy and run, and still a heck of a fun car to drive! I'd be glad to own one!