people keep trying to knock the M10 down but honestly if you give it a feel and try it far surpasses any other handheld in the same size range in just about every category that really matters, sony doesn't generally put out junk and this unit is no different
After ordering it, I started to read about people saying that the line in noise level is not good (for quiet stuff) and was a bit worried. Upon receiving the machine, it seems fantastic, although I haven't recorded a show with it as yet.
The built in mics are great and very quiet. The machine is solid and feels great in your hand. The limiter actually seems to work to prevent nasty sounding distortion if your levels are a bit high (unlike my Zoom H4 and Fostex FR2-LE). The mic in and line in seem to be quiet and provide a lot of gain. The display is large and easy to read (especially in regards to checking your levels). Unlike the Sony DAT's and HI-MD's, it seems that if you need to turn the record level down near 0 to keep the meters from going over 0 dB, you will NOT get brick wall distortion (although this may not be true for a hot sound board feed). The built in mics will handle a SPL that is quite high (rated at 123 dB by Sony). Also the machine is very easy and intuitive to use, the head phone amp is quite good, and the battery life is beyond belief. So far I can't find ANYTHING wrong with it.
Can't wait to record my first show with it.