I have just discovered by chance another very interesting tool included with MacOS X: FileMerge. It is just a simple file/directory comparer. Simple... but it looks great and seems to work even better:

FileMerge: to compare files in MacOS X
Seems that FileMerge dates from old NeXTStep days. Good idea that they kept the application. It is thousand times better than WinDIFF that Microsoft provides on some of his tools. And has a much nicer and convenient interface than WinMerge or the (commercial and reputated) Beyond Compare. A good reason to be glad to use an Apple computer (to compensate some other times I may feel dissappointed).