The difference is that with these new "straight blade" inlets, you must use the matching cord supplied exclusively by the same company. Very convienent. How lucky for us! :R
Here is a cut/paste from their site.
"Replaces your old 30A RV inlet (locking) to a standard Straight Blade style TT-30 connection found on most RV cords. This product is only available from Conntek Integrated Solutions and will only work with their cords. Lucky for you we have the 30A Straight Blade Inlet Cords in stock!"
I don't see a single thing about them being any "safer" than the standard locking cord. The cords they supply also lock on - only through the round ring on the cord rather than via the blades themselves. I would certainly think twice about purchasing it seeing that you need to not only purchase the inlet but the matching cord also.
Barney