Looks like Flyisght has been reccommended. Haven't wanted to know before now. I want to know as much data as I can after each jump. I own a Phantom3 and a V4 now. I also already own a Neptune and according to the website any paralogger will do.
Looking at the website the software looks complicated, unless that's just me. I am sure it isn't complicated at all.
There is no need to buy any extra software at first. Flysight has a Windows and OS X data viewer for quick reviews of your flight. Uploading into Paralog is valuable if you want to analyze the competition window.