I've used a bench, the second one pictured, strippers, the EasyLoader, and LULA.
I ended up settling on a LULA.
It's not THAT fast (strippers are faster in practice), but they are very easy.
- LULA: Very easy and compact. Can end up denting the cases if you have a very strong mag spring (about the last 20 rounds in a Beta C-Mag). Stays attached to the mag. Great for out in the gravel pit where you don't want to drop anything. Small enough that it fits well into a range bag.
- EasyLoader: I used it for the AK. Holds about 22 rounds in the tray of 7.62x39 so it must be used twice for a 30rd mag. I always had the rounds get bunched up. Since I had to screw with it all the time and due to the size, I sold it and got a LULA for te AK.
- The bench...really cool. But, it's huge.
- Strippers: very fast. And I've cut myself a few times. I got tired of it.
Night before a shoot/competition, I'll load up all my mags, then throw a few extra boxes and the LULA in the bag just in case.
BTW, the LULA pictured at the very top is for an AK/Galil.