The ETS loader uses the clever idea of skimming off rounds from the type of ammo boxes where the rounds are arranged in nice straight rows. While this is a clever approach, if you are loading loose rounds such as from ammo cans or bulk ammo, the ETS loader will no longer have a speed advantage over a LULA.
For a while, I used an Uzi speed loader depicted in this video:
https://www.youtube.com/watch?v=nADnJSdSKQM
You get the illusion of very rapid loading until you factor in the time to arrange the rounds one at a time into the loader. When I actually did some real world tests between that and the Uzi LULA and measured the TOTAL time involved getting rounds from the box into the magazine, I actually came out ahead using the LULA. It takes longer than you think preloading the loader one round at a time.
If you are not loading from a box of ammo packaged in straight rows, and you are using an ETS loader, you are in the same boat as using the Uzi speed loader. For me, it was faster to use the LULA. Amazing but true.