Help with Set Up

Hi all

I'm after some expert advice on my set up. Currently using a Rega Mira/Fono MC with project carbon arm/Project Xperience TT/Rondo Red.

I've had the rondo red on for a long time (4 years), sporadically used. but way beyond recommended hours usage so thinking of a new cart.

The debate is whether to stick to MC (which is expensive) or go for an MM cart, which my Rega Mira can use without Fono ,sell the Fono and put toward new speakers (currently using ancient AEGIS Ones)

I know there is always a trade off somewhere but will I lose a lot of quality by going from MC to MM? 

I guess this is s value question really- would the money be better put toward speakers or maintaining MC cart. 

If anyone has suggestions on carts that would also be useful- although I've had the TT a while I've never done any upgrades on it and all the info out there is overwhelming!