The actual implementation of the stats is in flux while balancing.
Vampyric recovery seems to be too weak at low levels and too powerful at high levels because players are able to kill more monsters faster.
Resistances are a logarithmic scale so you never reach 100%. The first +1 reduces by 1%, the second +1 reduces by 1% the remaining damage, etc. The formula is:
damage taken = damage * (0.99^RESIST)
+10 = 9%
+20 = 18%
+100 = 63%