The McFadden loader is great. Mine is set up for Ruger Mags, but still works good enough with Buckmark mags for me not to mess with the screw on it. It takes just a hair of messing with it to figure out how to make it load quickly, but no issue. Pop the mag up and down a little and make sure you hold it upright so a round doesn't go in standing straight up.
If you use waxy lead bullets, it will get a buildup inside overtime and they will be sluggish to move. With copper washed bullets, they load really easily. It takes apart with 5 screws and splits in half to clean out the insides. I cleaned mine last night actually. 2nd time I've ever done it and I've had it a year and a half, and loaded likely 10000rds with it. First time I cleaned it with hot water and dish soap. Nope, this time I just sprayed WD-40 on it, and wiped all the gunk out with 1 paper towel for each side. And wiped it down clean as well so no WD-40 residue was standing. Only thing I could think of would be not to overtighten the screws or let them go back in cross threaded, as its just plastic. They run like $20-25 most of the time, and they are worth it if you have multiple magazines. 5 empty mags, one box of ammo. Dump it in, close the lid, and go to town.
Aguila SV gunks it up real quick.