Yes, I have and do.
The site provides one with access to the latest data from PUBLISHED sources (e.g., Hornady #7, Barnes #4 (and #3), Lyman 49, Sierra #14, Speer, Swift #1, Hodgdons, Handloader Magazine) EXCEPT DATA from LEE MANUALS. However, I know this to be true only for the .300 WSM (the only gun I load for).
Oftentimes, it is throught the loaddata site that I learn about newly published loaddata (i.e., release of superperformance load data, release of data for Speer Deepcurls that includes newer powders, e.g., RL-17).