Even back when Sony first touted PS Now, the very idea of a streaming-based service for games felt like it would encounter myriad problems both on the server-side and if your own connection was anything other than immaculate.
Even with a 60MB+ setup input lag can be just a fraction off - enough to make something like Ninja Gaiden or any reaction-intensive game unplayable.
Fans cried out, "Why can't we just download the game to our console for a limited period instead?!", and this is exactly what Microsoft allows with their Xbox Game Pass.
Rather like the furtive days of HD movie rentals on Xbox Live, the Game Pass lets you install games rather than stream, eliminating the input lag issue completely. Microsoft also bolster their 100+ strong library with scores of Xbox 360 games and Xbox Live Arcade games ported from other systems like say, the PS1's Castlevania: Symphony of the Night.
There's no comparison here - for quick access to many past generations of games, Game Pass completely destroys PS Now.