I would recommend the D100 if your getting a new one. Two reasons, first you get this nifty remote with a new D100 that is very useful for stealthing....that if you bought an M1, it would cost you another $100 or so. And also, the D100 is a non professional unit, meaning that if Sony still does flat rate repairs, the D100 qualifies, while the M1 does not. Only reason I add the qualifier is because I have heard conflicting stories as to whether they still do flat rate.
Regardless, the remote is worth it IMHO.
Nick