You do realise you can decompress .rar using 7zip right?

But the scene releases are not using 7zip to create the rars, are they?

Among the movers and shakers in the scene, isn't there generally a predilection to use free software over non-free software? E.g. the only time I run across matroska contained movies is when it's released from the scene.

Not really. There's a general predilection for the best software available, especially since they're unconstrained by purchase costs. Often the free program is the best, but not always.

"Best software" - Are you joking? Scene releases use winrar mostly for packing and splitting. Usually null-compression is used.

Yeah it's usually an ISO within multiple RARs within multiple ZIPs. And this is when they don't act playful and use an obscure archive format that can only be extracted with a (paid or free but infected) closed source app.

Depending on the platform I'm using I have some code in bash, Powershell and C# to deal with this. Non coders must have a hard time !

Jdownloader automatically extracts archives, no fancy scripts needed.

From my observation, most downloads are rar format (95% at a guess), but it doesn't really matter if it's rar or 7z as the differences in resource usage are negligible.

The good news is that most archives support free extraction of both formats.

What formats are you referring to? o.o

It's bin a while since I encountered it, but I remember having to hunt for MagicISO or PowerISO to open several archives that I couldn't find anywhere else.