Penetration and cast level. Also, blood vengeance.

[mivayan]

UncleYee said:
For ex, are these equally hard to resist?

Yes.

edit: oops. Llamabeast is right. erm. I seem to have failed very basic math here. It's +1, +1, +2 penetration. (/edit)

Second, does either or both spell penetration bonus and higher level make for a more effective (each reflection less likely to be resisted) blood vengeance?

Penetration does't affect blood vengeance.