As part of your search for the best cajon, please talk directly with local cajon builders. These links list 350 cajon makers in over 50 countries. Locally made cajons contribute to your regional economy and provide an environmentally sound alternative to shipping a plywood box full of air halfway around the planet.
YouTube channel with playlists for many countries:
Note that not all manufacturers have current YouTube videos. The links on this page go to lists which includes websites and Facebook pages which may contain videos not on YouTube. The links from this page are current and actively maintained, the YouTube playlists are less frequently updated.
Cajons are one of the worlds most universal instruments. Drums speak to humans from the heart. Good cajons can be built by local woodwookers with simple tools even in remote areas. Listed above are links to the cajon drum builders of the world as retrieved by Internet searches from March to June 2018. I am sure there are many others not listed. Please send me updates and correction if you have additional information. Thanks.