Wether the full version is worth it depends on your needs. Would you be satisfied with predetermined (albeit very good) instrument placements? Or do you want the freedom to position instruments everywhere freely?
Do you want control over which microphones are used? Or do you want to be able to pick your own ones?
Are you the type of person who is satisfied with the basic sound of the reverb as is (which is very, VERY good)? Or are you someone who cannot live without the ability to tweak the tone to your absolute liking?
If your answers to all the above is the first answer, get Essentials. If your answers are the second, get the full version.
I immediately bought the full version (Essentials wasn't out yet) and, while expensive and not without fault, I see it as one of the best investments I have ever made. I myself would find Essentials too limited.
However, in order to really get the most out of the full version, I highly recommend knowing your reverbs, also at a bit of a technical level. The full version is not a beginner's plugin. It's not obtrusively difficult, but you have to know your stuff to really fully utilise it.
Hope that helps.