I had a K. Yairi NY-16b for a while. It was very well built, extremely light and incredibly hard to find in North America. I looked for two years before I found it on ebay. Unless things have changed they are sold in Asia and Europe but not in North America. I kept it for a while but sold it and kept a Larrivee OO that I still have.
The Larrivee has a longer scale and had a fuller sound than the Yairi. I've ended up with a couple of OO Larrivees (Shameless plug I have a Larrive OO with a Flame Maple back & sides and a Sitka top for
sale in the classifieds).
Unfortunately I have never played a OO Martin so I can't give you a comparison. If you really want a Martin what about OO-15? If you like the slotted head stock look for a Larrivee OO-50/60 or a Tanglewood TW-73wn (not as nice as the Larrivee but less expensive).
Cheers