I'm really late to reply, but I was away...
I'm afraid you got that in reverse in regards to the 960/S90. I
should know, I had a 95, 960, a 96 960, a 97 960 and a 98 S90.
The nbame change in Jan 97 from 960 to S90. The 98 is teh last year
and the best one to get. The 97 and 96 are also fine. Saty away from
pre 96 model. 95 was a major overhaul of the car. Famous problem
previous to overhaul was timing belt braking. The 92 has a porous
engine block as well as many other annoying things.
The only real problem is that the 960/S90 tends to eat the brake pads
and the discs always get warped. Other than that, it is your typical
Volvo. A/C needing repairs after 5 years. Parts are very expensive.
Easy to maintain.
The V70 is a rebadge 850. Volvo terminated in 98. After they became
Ford. Be warned. OTOH, if you enjoy frequent trips to the dealer you
will be pleased.
The S80 is a lemon during the first 3-4 years of production. The last
or latest years seem ok. But has poor resale value due to early
reputation.
S60 are kind of fine. They have their little annoying problems like
all Volvos produced under Ford.
My 2 Canadian cents, which currently worth more than 2 US cents