The main advantage you gain is that you will be able to use LOMC cartridges. Other than that, I like the idea of getting away from the "plug In card" that’s inside the 99, and getting a proper external unit. Love your system, keep in mind that the phono pre is the gateway to excellent vinyl sound, so spend accordingly. I use the DV20x2L w/Manley Chinook and I love it over the Clearaudio Maestro v2 ebony. Also, all the $200 to $500 phonos sound like crap and even up to a $1200 Musical Surroundings Nova, though the latter was a vast improvement, it wasnt until I went for a Chinook (at around 2k there are several brands to choose from) that my vinyl world really improved to vastly higher level of detail and "aliveness" the others lacked.
Matt
Matt