I recommend the Sony MZ-N10. It has the ATRAC Type-S DSP, which will make your MDLP recordings sound better. It also has a faster version of NetMD (up to 64X recording at LP4 - DAMN!), so I'd recommend it for that as well.
I'm not sure about the Sharp units, as I'm still on my first one (Sony MZ-N1). Although, it'd be interesting to know the difference (if any) between the Sharp and Sony ATRAC encoders.