The Professional (Pro) version of MyEclipse
is a bit more expensive (see the purchase page
for the latest pricing) version of MyEclipse
that includes certain advanced features specific to enterprise level developers. The reason for making this new version available was to allow users not interested in these enterprise features to keep paying the lower fee for the Standard version that will continue to get new features, updates, etc. without incurring the cost of Professional level features that they won't use or find helpful.
For a comparison of the two versions (and the other editions) click on this link: http://www.myeclipseide.com/module-htmlpages-display-pid-1.html