It's hard to find fault with Korg's unprecedented recording quality and file format resolution, but the MR-1's poor suitability as a truly mobile device makes it tough to recommend. Rated at 2.5 hours of battery life while recording WAV files, or just 2 hours for DSD file recording, the Korg MR-1 just isn't cut out for the demands of mobile recording. To be fair, running an audio chip at the unprecedented 2.82MHz required to handle DSD audio must require some serious power--but if you can't take it away from a wall socket for more than 2 to 4 hours, then its usefulness is limited as a mobile solution. As of January 2008, Korg is now shipping the MR-1 with an extra external battery pack that doubles the device's recording time. Unfortunately, the external battery pack adds awkward bulk and still places the MR-1's battery life short of the 12 hours boasted by the Sony PCM-D50. To make matters worse, we also found the Korg MR-1's charge time to be painfully long. During our unofficial preliminary testing, it took the Korg MR-1 between 3 to 4 hours to reach full charge using the included power adapter.
The small lavalier condenser microphone included with the Korg MR-1 barely taps into the device's sonic potential. Recordings made using the microphone in both indoor and outdoor situations were riddled with microphonic artifacts caused by movement of the cable, or transference from the surface the microphone was placed on (using the included stand). If you're determined to use the Korg MR-1 for nature or concert recording, expect to shell out some money for a better microphone.
Beyond Korg's innovative DSD recording feature, there's no reason to choose the Korg MR-1 over its less-expensive competition. To Korg's credit, the MR-1 is the least expensive way to capture and transfer recordings at a pristine 1-bit, 2.8MHz resolution; however, audio professionals will likely prefer the rugged construction and standard inputs of the Korg MR-1000.