I'm an LS-10 owner. Overall, I like it, in spite of some limitations.
Pluses:
- Small size
- Excellent build quality
- Long battery life (LS-11 lasts longer)
- Easy-to-navigate menus and good display
Minuses:
- Mics are OK, but could be better (LS-11 reportedly improved)
- Small, hard-to-read level control
- Slow USB interface
- Possibility of hum with stealth mics (see below)
I haven't been able to determine if the hum problem (~350 Hz square wave hum) is unique to my LS-10 or not. Basically, if I'm using external mics, and the capsules or cord are close to the LCD or the mics are on my body and the LCD faces my body, and I'm not physically touching the recorder, I'll get the hum. Before I figured this out, I had a few pulls ruined by it - all my attempts at filtering it have gone nowhere. When I position the recorder correctly, I get no hum whatsoever.
The built-in mics are a bit bass-deficient - I normally EQ the bass upward to compensate. Some here have said that they flat-out hate the LS-10 mics, but I'm not one of them. The general wisdom here in any case is that internal mics are more of a last resort for when externals can't be used.
When I use Sound Professionals SP-TFB-2 in-ear mics, I get the best results by NOT equalizing anything, and the same goes for AKG Perception 170 > E-MU 0404 USB > analog out > LS-10 line in.
The budget AKGs are noticeably better than the internals (and provide the option of working with a variety of patterns), but they're very unstealthy and require an external preamp.
In spite of my general dislike of Sony (rootkits, anyone?), if I were starting over, I'd probably go with the Sony PCM-M10 for small and stealthy. In a radical departure from typical Sony practice, the M10 accepts standard MicroSD cards.
The Marantz PMD661 or Edirol R44 would be my top candidates for phantom-powered mics if I were starting from scratch, but at this point (when finances permit) I'd more likely stick with the LS-10 and add a Naiant Littlebox to provide better portability with the big mics than the E-MU box.