Which digital recorder?

I did a topic search & didn't find any relevant posts, so I'm hoping folks here can give me some input.

I've been tasked by the fine arts dept. director at my kids high school (yeah, my arm is still a little sore....) to look into the purchase of a multi-track digital recorder.  

I have quite a bit of past experience in live mixing, and some with multi-track tape mastering. Unfortunately, most of what I know about the new breed of digital recorders is what I picked up in an afternoon at GC, plus what I've been able find on the web.

The school auditorium where most of the recording would be done has excellent acoustics, and a somewhat dated, but fully adequate mixing panel & PA system.

The main use will be to record live performances of the various choir groups, band, orchestra & instrument ensembles.  Ease of use is important, as she would like to have student tech crew members learn to operate the equipment.

From what I've seen so far,  a minimum of 4 simultaneously recordable channels would be required, and 8 would be nice (to add some additional section or soloist miking for example).

The two units I've seen so far that impress me are the Yamaha AWG16 and Roland/Boss BR-1600.

Anyone here that has experience with either and especially both of these units - your input would be appreciated. Input on other mfg/models would also be appreciated.

Thanks!