Having tried all three programs I can tell you that the one that made the difference to me was WinAutomation.
It's such a user friendly program, less than basic programming skills are required in order to build a program, it literally saved me from spending loads and loads of hours trying to learn a programming language to achieve what I needed!
All three programs are good, but I'd say that for the Macro Scheduler, you'd need to be at a very good scripting level and as far as the Macro Expert program is concerned, it lacks some very handy features that WinAutomation has, such as the fact that you can generate an executable file of a job you created and run it in other computers without having to install the program it self first, or you can also use the exception handling features for the jobs you create so that you limit the possibilities of a job not completing due to unexpected errors that may occur. What I also found really interesting in WinAutomation is the fact that you can also use FTP Services without having to call in an external program, which also saved me a lot of time sending clicks and keystrokes to get the cursor to the places i wanted in external programs such as filezilla.
Another major issue, that made me use WinAutomation more when I first tried it, is the fact that I could post questions to the forum and get answers promptly and also read other users' questions and learn things that could occur at a later point.
There are so many things..i could keep going forever (!) but i think you really need to give them all a try and see what suits your needs best.