Doc,
I also have a DGX-305 which I think is a great value for the money too. I put a 64 meg SmartMedia card in it which I got for next to nothing on e-bay. It is just my home keyboard.
As you say, it seems you can only have one user style which is disappointing. You can have 900+ midi files loaded. I am not happy with the two main Grand Live! and Warm Grand Live! piano voices. They sound great in the middle registars but the upper scales sound "thin"(I don't know if that's the word) and dull to me. Luckily, the third voice which is the regular Grand voice sounds great to me in all octaves and that's what I usually use. I find that I need to have the panel-sustain on most of the time or the sound decays too fast for me. I use a pedal sustain as well sometimes. The keyboard action is more like a piano then the keyboard I was used to. All in all, I like it.
Chuck