? Regarding Nitro Tranny vs electric tranny

[JThiessen]

Now that i have my first E-Revo done, I am considering converting my second one. However, I'd like to tak eanother look at using the revo tranny. But I dont understand tranny operations well enough to make the decision yet. I understand that on electrics, the motor supplies the braking and reverse operations, thus the entire gear train turns the same way as the motors are. On a Nitro, there is a secondary set of gears that will engage to provide reverse. Thats about as far as I understand it.
What does a center diff provide?
What features in the nitro tranny prevent it from functioning like the emaxx tranny? I'm sure this relates to the above question.

Also, now that Traxxas has released their own center diff, does this change the scenario (compared to the posts about creating a center diff)?