I worked for Unisys in 2002 or so and I always thought it was funny to see a mainframe able to run Pinball...
For some time I defined a "serious computer" as something that didn't have ports for keyboard and monitor.
Having said that, the pre-x86 A series were pretty cool. And ran the most user hostile OS ever created, to the point its very name was used for Tron's villain.
Unisys always had a smaller mainframe share than IBM, and they stopped making new chips sometime in the 2000s.
For at least ten years the fastest Unisys mainframes have been very big (proprietary) x86 machines running Windows with a Unisys mainframe emulator.