They make some good stuff HOWEVER a friend & I each, independently, bough a ZOOM16 to use as a stand alone recorder as well as an interface to REAPER.
Both units across a 6 month period had chronic failures - the battery & external power pack systems failed. It's not the batteries, not the battery connections, not the "wallwart" nor the connections to the units but the circuitry handling the power once it enters the machine. I assume the caps & resistors that regulate the voltage to and at the internal voltages failed on both units.
Weirdly both machines will run on power supplied by the USB connection to a computer.
No longer can they operate as stand alone recording devices...they have to be tethered to a USB power supply.
Sad thing as the units worked fabulously as stand alone, do a great job as interfaces and also double up as Mackie external controllers for Reaper and other DAWs.
Two out of two could be coincidence, may be a result of dealing with a different mains voltage, (Australia being 220-240), but both failed.

Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe