In the YouTube video titled "Van Halen - Why Can't This Be Love (1986) (Music Video) WIDESCREEN 720p," Eddie Van Halen is seen performing live using a Kurzweil K250. This video was provided by TheManFromCabo.

Brian May used the Kurzweil K250 in the recording of "One Vision" and most of the album A Kind of Magic. It is believed that this instrument originally belonged to Freddie Mercury, who used it on his 1985 solo album Mr. Bad Guy. An image from the recording session of A Kind of Magic supports this information.

The Kurzweil K250 is an early digital sampler keyboard. It was used by Prince on Around The World In A Day and Parade for string, orchestral and choral sounds. It was also used by Dr Fink on the Parade tour.

Richard Wright began using the Kurzweil K250 synthesizer/sampler during the production of "A Momentary Lapse of Reason." According to Fika, he later upgraded to the K2500 for the P.U.L.S.E. Tour.

From the July 1990 issue of Sound on Sound, a list of instruments used by Vangelis:

Akai S900 Akai S1000 Direct Sequencer Emu Emulator II Korg DSM1 Korg M1 Korg Symphony Kurzweil 250 Roland D50 Roland Juno 106 Roland MKB1000 Roland MKS20 Roland MKS70 Roland MKS80 Roland S50 Roland U110 Sequential Prophet VS Yamaha DX7 II Yamaha EMT10

Stevie is pictured here, circa 1984, with the K250 and its inventor Ray Kurzweil. Stevie's role in the development of this instrument is detailed in this CNBC entry dated Apr 21, 2016.

TLDR: if Stevie invites you to his studio, and asks you to make a synth, you make that synth.

Used on Perfect Machine, as specified in Herbie Hancock’s Electronic Instrument Glossary from September 14, 2016.

Kurzweil K-250 – First released in 1984, this sampler synthesizer was able to produce sound derived from sampled sounds without the need of a disk drive. It featured both acoustic and ROM sounds built in with twelve-voice polyphony. Herbie used this instrument on his album Perfect Machine in 1988.

I worked with Kurzweil in the 80s and owned a K250 Expander and MidiBoard. You can clearly see the K250 on the left side of Keith's 1986 keyboard rig. You can also clearly hear the very distinctive K250 CHOIR patch from Sound Block A all over "The Score" - both live and on the studio recording. You can hear the K250 percussion (claps, snaps and shakers) all over Touch & Go as well. The "Endless Glissando" patch as well as the K250 choir and strings are all over "Mars, The Bringer of War."

The MidiBoard is the large 88 note controller placed on top of his GX-1. See the video.

Enya is credited with using the Kurzweil K250 on her album "The Celts," originally released in 1986 and remastered in 1992. While the K250 isn't explicitly mentioned in the album credits, it was one of the primary instruments available to her during that period, alongside the Juno 60, DX7, and Emulator II, as noted on 45worlds.

According to the Kurzweil's website, Carin is a user of the Kurzweil K250.

"Because Burchill is known for his atmospheric tones, it is no surprise that he has experimented with and used several different gear setups throughout his career. The early ‘80s sound came through a Roland 501 Echo unit into a Roland JC120 amp. During the second half of the ‘80s, Burchill switched to Marshall JCM 900 amps, and used a variety of effects including and Eventide Harmonizer, TC Electronic 2290 delay, Roland GP-8, Yamaha Rev 7, and a Kurzweil 250 rack-mount sound module. Burchill used a ‘62 Gretsch White Falcon and a Fender Strat in the studio, and a custom thin-line Telecaster (notably on “Don’t You, Forget About Me”)."

As stated on his MusicDatabase biography, Lyle Mays used a Kurzweil K250 digital synthesizer:

Mays plays a Steinway Grand Piano with built-in MIDI. He has used an Oberheim 8 Voice Synth, a Sequential Circuits Prophet 5, Kurzweil K250, Korg DW-8000, Korg Triton keyboards, and many more.