I currently use a mana spiders build (what my profile shows). So mana on the SOJ is not an issue for my build.
Yes but a -10 mana on Bear should be worth something and you get another 100ish mana on top. For a bear build, mana = damage. And really, with or without SOJ, Bear should maul through trash enemies just fine. It is elites that are causing problems?
I feel there are only a few runes that are worth SOJ: SB, Bear and Firebats. The rest are okay.