Super Black is technically "illegal" for broadcast NTSC. It is used primarily for generating keys for CG elements on older analogue editor systems. These days most online systems will import imbedded alpha channels for mattes, or allow a separate matte input. (a,b,c roll)
Typically NTSC safe colors range from about 12 to 204 on a scale of 1-255. Pure uncorrected CG elements will range the full spectrum from 1-255.
There a few reasons you may want to go to superblack. 1) you're contest is web or computer only format, so the "legal" colors don't apply.
2) You are generating a matte for use in an older on-line suite.
Generally, I would output to uncorrected colors if you are only doing CG. It can always be color corrected online and is more precise with scopes and the like.
If you are doing compositing to live action, it may be wise to match to NTSC in the composite so that you don't get 2x the color correction on the live plate if your CG happens to be outside legal. (They will have to color correct the composite because of your CG, and thus the original footage will be washed out.)