Totally worth it if you're not into playing alts. Each MPG trial raises your resists, and resist cap by 3, iirc. And DoN tiers are pretty sweet. T1= raises max stats, and stat caps by 10, T2=an additional 2% to health and 250 m/e, T3= +1 to buff cap, T4= 1% increase in your innate crit chance for heals/spells/melee, and T4= raises your chance to innately resist a detrimental spell, % unknown.