The differences between these two pianos and the smaller MDG100 micro grand is that the S & MG pianos & benches are built with larger, thicker legs & pedal lyre which makes for a sturdier piano, have 5 tracks of recording and playback (the MDG100 has 3), the S & MG pianos have 6 built-in speakers (the MDG has 4), and the S & MG pianos do not have an iPod docking station and the MDG does. The iPod docking station can be handy because the sound goes through the piano and you can play along, but you can also run an iPod through the regular audio input jack on the S & MG pianos which is essentially doing the same thing. The audio power on all three pianos is the same at 120 watts (very good power) and all of the piano and instrument sounds, rhythms, and other functions are identical.
If you want to learn more about the S350 & MG350 digital baby grands, go to my blog review of the smaller MDG100 at the following link and check that out. Then you'll get an even more detailed review on these pianos: Suzuki MDG100 piano review.
A good alternative to these Suzuki pianos is the Samick SG450 which you can learn more about at the following review links on my blog: Samick Digital Baby Grands
If you want more info on these and other pianos and lower prices than internet discounts, please email me at email@example.com or call me direct at 602-571-1864