The Porlex is expensive for what you get. It used to be cheaper. The Rhinowares grinder is very similar and still cheap.
Stainless steel 34mm burrs also cut significantly faster and more consistently in a similarly sized grinder. This is the main reason you want stainless steel.
I wouldn't worry about longevity since we're talking about a decade or more for whatever type you chose. But yes, ceramic will last longer.
In fact if you don't want the grinder to fit in the plunger of an aeropress, you can get Taiwanese grinders with stainless steel burrs, well stabilised shafts, ball bearings, a milled Al body for less than the Porlex mini and only slightly more than a Rhinowares.
> A quick Google search of ceramic vs steel burs also seems to indicate the ceramic offers better longevity.
I have a theory that people who start with a Hario Skerton or its clones (all of which have ceramic burrs) tend to be turned off manual grinding because of how bad the grinding experience is.
Steel burrs supposedly cut better and faster.
Admittedly, I've tried my friend's Porlex Tall, and it wasn't unpleasant to use.
Not that I want to pick a fight, but I'm sharing this more for other readers' reference.
I've had my Porlex for a little over 5 years now, use it around twice daily, and have had zero issues.
A quick Google search of ceramic vs steel burs also seems to indicate the ceramic offers better longevity.
Why else do you say Porlex is terrible, aside from being ceramic?
Its build quality is excellent. Well worth the price.