Thanks for the appreciation, but the real work was done by those who created each of these community versions.
These installers are actually very simple. All they do is copy a community version of ipdf over the default iRex version. This means that you cannot have multiple versions installed at the same time. All this set of installers does is make it easier to switch between the different versions, by copying across the version you have chosen. The links at the top of the thread show the original posts from which the versions have come.
There should be no harm at all in switching between each version depending on your needs. One difference you might see is that gmt's "for editing" version is based on slightly older ipdf code and does not have the forward and back buttons (it might also be missing some other features as well, but I have not noticed).