BUFF’s airframe design is older. The current flying are not.
There is no comparison between the Bear and the BUFF, aside them both being heavier than air ships.
The most current B-52 variant, the B-52H, is the only version that the USAF is still flying. All were manufactured between 1961 and 1963. Certainly there have been ongoing updates and modernization programs, but the Russians kept the Tu-95 in active production for much longer (pretty much up until the fall of the Berlin Wall and all the Glasnost / Perestroika stuff became the order of the day).
The two aircraft were indeed very different approaches to the same objective.