Everything seems to work well (many tests making random changes over various meshes went good), but the code is a bit complex and hard to follow, due to the various possibilities of invalid poly/loop combinations… Code also makes more operations than previous tri/quad faces version (hence is a bit slower), but I don’t think we can do otherwise, it’s just the price for bmesh flexibility. ;)
Note: added the py script I used to make the tests, under source/tests/...