I'm a recovering MD user and the PCM-M10 is superior in virtually every way.
1) Because the PCM-M10 looks pretty much like a point-and-shoot camera, I take it to gigs in a camera case on my belt. Leave the case open a bit and you can see the LEDs. You can't see the display, but that's showbiz. You'll get used to it, and with the limiter the PCM-M10 is pretty forgiving.
2) There is a record button on the remote, and you easily remember where it is. (Record, Pause, Trackmark and Stop are the four buttons on the remote.) So there's no need to find the button on the unit. But if you really want to be fiddling with the unit, even if you don't want to leave it lit up, you'd just learn the position of the button--it's raised, the unit is asymmetrical, you'd have muscle memory. The Play button actually has a little raised dot on top of the raised button to orient you even more easily.
3) See 1. In the camera case, the switches on the back will not get accidentally moved unless you move them. In a tight jeans pocket, maybe conceivably but you'd probably have to work at it. They click into place, and they are very close to flat so someone would really have to be lap-dancing your unit to move them. In which case the concert would probably be a secondary concern.
4) Your MZ-RH1 is worth a lot since it's the only one that uploads legacy MDs. Check out the Ebay prices. Other MD units, probably not so much...
http://www.ebay.com/sch/i.html?_from=R40&_nkw=mz-rh1&_in_kw=1&_ex_kw=&_sacat=0&_okw=&_oexkw=&_adv=1&LH_Complete=1&_udlo=&_udhi=&_samilow=&_samihi=&_sadis=200&_fpos=&_fsct=&LH_SALE_CURRENCY=0&_sop=12&_dmd=1&_ipg=50