Hi Mauro,
I have recently upgraded from the Stmnt to the standard version; from my POV, it's worth doing. The bigger brother gives you better separation and colour of tone. The acoustic image can become extremely wide (obvs depending on the cartridge).
Saying that, that of course depends a bit on where you want to go cartridge-wise. Personally, I liked both amps best in MC configuration - the higher the gain, the better.
Best,
Oliver