I have a DGX 305. You can load as many styles as you want to the SmartMedia card
BUT..you can only load one style at a time into the ONE user area. You cannot play styles directly from the SmartMedia card that I can see. This is a drawback to this machine for those that would like to do this. On the other hand, you can load around 950 or so midi files on the SmartMedia card and play them directly. It will also show lyrics, chords, and score if you want. The keys are box style and have a different feel than the PSR series. For the price, it's a great keyboard though.
Chuck