Pats--
I came to the Sony PCM-M10 from MD as well. It's an improvement in every way.
1) But internal mics for metal? No. They'll still overload.
2) Yes, it has a Hold switch. It's the Power button slid the other way.
Photos here will show you all the views and controls.
http://www.bhphotovideo.com/c/product/638090-REG/Sony_PCM_M10_BLACK_PCM_M10_Portable_Audio_Recorder.html3) It has 4GB of internal memory and will take an outboard microSD card of 32GB--or even 64GB if the 64GB card is formatted to FAT32. High fidelity PCM/wav. recording at 24/48 is about an hour per gigabyte. If you do mp3 at 320 one hour is about 140 MB. So the internal memory alone would handle a four-hour hi-fi concert, and a whole lot more at mp3. And an external card---well, you'll just get totally spoiled.
http://www.sounddevices.com/calculator/index.html4) I don't know if you got in on the Church Audio deal. They are made for high volume and would be your best bet. That deal included two pairs, and if you're broke you could sell one in the Yard Sale. I'd keep the omnis because I prefer omni recording.
Otherwise a good combo, around $130, is the Soundprofessionals BMC-2
http://www.soundprofessionals.com/cgi-bin/gold/item/SP-BMC-2(Get them with the clips unless you're going to sew them into a hat or something.)
plus a battery box, SPSB-10 (you don't need or want bass roll-off):
http://www.soundprofessionals.com/cgi-bin/gold/category/310/micsThe battery box feeds extra power to the mics that helps prevent them from overloading. You can feed that signal into Line-In, which bypasses the preamp at the Mic-in jack, another place that can overload (and that's what often overloaded in MD). The PCM-M10 preamp at Mic-in is more robust than the one in MDs, but metal volume is still too much for it.
If you got in on the Church deal, there's a preamp in there too, so you don't need a battery box. At a loud concert you just turn the preamp down low or to zero and run through Line-in.
When I got the PCM-M10 I could hardly believe how much less hassle it was than MD. Files are just .wav or mp3 files that upload directly from the card or internal memory--no SonicStage madness.