

In most cases, most release groups already fine tune encoding settings towards various balances of file size and quality, so the best option is to decide on a set of release group whose standards meet your needs and just use the files as they come without further modification.
Applying lossy compression to a video that’s already had lossy compression applied to it degrades it unnecessarily, so if you’re going to compress it yourself, it’s best to start with the remux, aka the original media file.
I’d personally recommend releases from members of the qxr group and Vyndros.
Their decisions seem to conveniently become ‘mistakes’ whenever there’s public backlash…