Rolando is a busy man, and his work usally comes out later than A-Patch. I like A-Patch much better, it just seems more professionaly done. However, it has one or two annoyances. It refers to Windows Live Messenger as MSN Messenger and does not end the process or msnmsgr.exe for you
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Each contain unqiue features. A-Patch has a few extra small ones, mess Patch can change messenger's design and add certain buttons. Really it is up to how you use messenger.