It's a nice little film. You can probably guess from the title woho it's about. No major revelations or anything but a few interesting facts I didn't know about the original Star Wars trilogy for example who originally stated that it would be pretty cool if Vader was Lukes dad (before the script for Empire Strikes Back had even been written).
It also turns out that in his older age, Prowse can do a pretty spot on James Earl Jones impression.
Definitely worth a watch if only for curiosity value.