I've traveled to and edited OpenStreetMap on the ground in over 30 countries around the world. I am particularly familiar with the Caribbean, Central/South America, Middle East, and the western US. I've been working with OSM since 2009.
My OSM stats: http://hdyc.neis-one.org/?Canyonsrcool
My heat map: http://yosmhm.neis-one.org/?Canyonsrcool
I edit all over the world, but countries I have visited personally and in which I do deeper edits of OSM include:
USA (Intermountain West)
Turks & Caicos
Trinidad & Tobago
United Arab Emirates