Not to confuse, but diff can recurse too. I did the same thing when moving files around. The command I used was:
diff --recursive --brief /path/to/dir1 /path/to/dir2
With "--brief" diff will only output when files are different. Specifically, it'll say something to the effect of "/path1/file1 and /path2/file2 differ" or it'll tell you if a file exists in one directory but not the other...