Help me decide on my next cartridge (<$900)

They say that rule #1 of owning a turntable is -

“Do not spend more on the cartridge than the table”.  So, we are talking about <$900.

That being said, this is my current setup:

• Parasound Halo Integrated amp
• Pro-ject Debut Carbon Esprit DC turntable
• Ortofon 2M Blue MM cartridge
• Vandersteen 2Ce Signature II speakers

I like the 2M blue, but it’s getting up there in listening hours, and it’s the only cartridge that this turntable has had; so I don’t know what I’m missing by moving up.
I would appreciate any and all suggestions.