I have a couple of old power supplies in which Rifa brand metalized paper line filter capacitors (for 240V mains power) have failed - or may fail - like in this question here.
30+ years sounds pretty good for a capacitor, but researching replacements turns up lots of opinions about brands and references to different types and materials.
Similar metalized paper capacitors are still available (Evox Rifa is now Kemet), which though a bit pricey have the appeal of looking like the original part. One downside is their failure is messy!
Alternatively there are cheaper metalized film capacitors with polypropylene or polyester.
Is there evidence for a best replacement type considering performance and reliability?