I've been using EVP for some time now. At the entry level, the nicest part is that you are able to download and install additional Models, Types, and Callsigns that are available from the various flight simulator sites. No longer does your favorite plane have to be referred to as "experimental."
If you use the View Missing Tool (CTL+M), it will even tell you what items can't be found and need to be either installed or created.
I recently got into the creating part of it when I was unable to find some aircraft model and type vcpmod files for planes I am using. I've been called eccentric and worse, but I think it's fun to hear ATC talking to UFO, Thunderbird, or Airwolf. Also, I was able to fill in some items that I was surprised were not on the standard list like McDonnell, Goodyear, etc. Between the documentation, forums, and frequent right clicking, I think I have the hang of it.
Also, if you like to get into the nuts and bolts of things, it is a good way to learn about what calls go where and how to fix them without necessarily creating a file. Sometimes you just need to correct the call in the aircraft.cfg file which doesn't work due to misspelling or wrong labels.
Hope that helps.
Bill