I think the brand doesn't matter much. They all work fine.

I will make a post about it, so it is easier accessible for others too.

TL;DR what I'll say:

• Expensive isn't much better per se, but there are still some with worse quality than others (unpuffed balls, etc.)
• There's "red" LECA (smoother surface, but more compact) and "grey" LECA (very lightweight, porous and floats). Both have their own (small) pros and cons, but still similar. I just mixed them by now for aesthetic purposes lol
• The size variation matters a lot. Bigger, rounder balls = more air gaps. Also, I've found smaller beads to also be less porous than bigger ones.
• You have to soak it first in pure water when dry. If you use tap water instead, it will soak up the minerals and leach them out over the next weeks and alter the water chemistry, including pH.
  You can reverse this pretty fast by boiling in rain/ distilled water. The pressure from the boiling will drive out the remaining stuff from the pores.
• All in all, aside from the dust and (often) leftover minerals in the beginning, it is totally inert once you've soaked it in pure water at least two times.

I made a guide a few weeks ago, here it is

LECA is expanded clay balls. Similar to pumice for example, it has a lot of pores, which draw up water by capillary action. It is constantly moist, but also highly aerated and my hydroponic medium of choice.

I also made a few posts about it, including microscope pictures and explaining the concept of semi-hydro :)

Lightweight Expanded Clay Aggregate. Basically totally inert pebbles that are very light and will retain a little water and draw a tiny bit up through capillary action. Used instead of soil for hydro and semi hydro growing.