I got my McFadden Lightnin' Grip loader today, and here's my thoughts. It works on everything I have EXCEPT the BX-25 magazine. If you look at the lips on the BX magazine, its shaped differently than all the other high cap mags. I even tried loading the first cartridge by hand, but no luck. The direction the loader positions the cartridge to enter the magazine lip doesn't match the BX magazine.
Here are the mags I have that the loader does work with, and works perfectly.
Ram Line 30
Champion 30
Butler Creek plastic lip 25
HC3R 25
Tactical Innovations 25
Once you figure out the loader(it comes with well written instructions), it will load a magazine as fast as you can pull its trigger. I loaded up about 200 rounds in various mags, and its quick and easy. I do have a bit of soreness on my trigger finger, as the loaders trigger isn't shaped as I would like, but I found that using the second pad of my finger, or my middle finger and switching between those different points on my fingers helps.
This loader works so much better that my old Butler Creek loader. The Butler Creek loader works, but was quirky, and took some finesse to get it to work easily. The McFadden Lightnin' Grip Loader is a winner for anything but the BX magazines.