I use a four-track digital recorder and a Mackie mixer for my keyboard and voice recording, it allows me to rework the balance and quality of the song.

1-Keybard into the mixer, channel 1&2 stereo
2-Microphone into the mixer channel 3&4 stereo
3-Output of the mixer into the four tracks of my recorder.

Advantages:
1-I can adjust both keyboard and voice to my liking.
2-I can add, through a channel impute the right amount of reverb to my voice.
3-If I wish I can play back the keyboard part and re-record my voice.
4-The recorder gives me the ability of putting tracks 1 through 4 onto track 1&2, allowing me to add another backing voice or whatever to the recording.

John c.