If I'm being perfectly honest, I must admit that "Stars" isn't that special in terms of its actual songwriting. It's pretty much a "Rainbow In The Dark" rewrite right down to using a similar song structure but trades the iconic keyboard line for a one line chorus enthusiastically shouted by every musician involved. It's still a pretty fun song and wouldn't have been out of place on The Last In Line or Sacred Heart, but it likely would've been seen as a solid filler track if Dio had been the only singer on it.
A friend and I once debated what singers would be on a modern version of Hear 'n Aid but this project could've only happened when it did and is best appreciated as a relic of its time. The driving rhythm, guest singers, and even the guitarists' contributions make it mandatory for 80s metal nuts but the typical structure and dated feel make it hard to recommend to anyone else. It's a fun listen and I'd probably get a copy if it were ever re-released. Rest in peace, Ronnie, no modern tribute could ever be as fulfilling as jamming this cornball.