RotW changed things. With all the extra -res equipment, 200 fcr eschuta nova can finally hold its own against self-wield infinity. The only problem is you need a really high char level and nice gear to get by without potting. The builds have about equalized in power now.
calculations:
200 fcr eschuta nova does 6k average damage every 7 frames, has -50 light pierce + conviction. Vs monsters with light res up to 35%, eschuta build does 43k DPS, and for monsters with light res up to 90%, eschuta build does at least 31k DPS. Vs light immunes, eschuta build does 15.4k DPS.
105 fcr self-wield infi nova does 5k average damage every 8 frames, has -100 light pierce + conviction. Vs monsters with light res up to 85%, infi build does 31k DPS. Vs light immunes, infi build does 19k DPS.
In summary: eschuta beats self infi for non immunes by anywhere from 0-40%, and loses by 19% against immunes.
200 fcr eschuta build has 3 more +sorc skills, which helps with ES, static, warmth, tstorm, frozen armor, and fire wall for optional hybridization. It has more resists, which means getting away with a lower level ES. With 1 pt ES, max warmth, and charms with decent life, your mana pool is still depleted before life, and the lower mana regen from warmth compared to insight is mitigated in part by the lower level ES easing the damage done to mana.
The more elemental pierce gear that gets introduced, the better 200 fcr nova builds fare against self-wielding infinity. If the crafted pierce charms get activated, even 200 fcr wizzy might blow 105 fcr infi out of the water.