Details: Not much, other than a certification leaking from testing firm Quietek, that states a TF300T received its marks. The original hybrid with the very litigious name, the Transformer Prime, was the TF201, and the primary Transformer a TF101, so it's a guess as to what gives this third tab-top a "T."
Likelihood: Fairly high, given the photo, the certification, and the tendency of companies like Asus to capitalize on success by producing many, many models.
Get excited?: If you returned or had your order cancelled for one of the earlier, often busted Transformers, maybe this is the model where the bootloader doesn't lock up, the aluminum doesn't knock down signals, and everything snaps together well. Maybe the "T" stands for "tested"?
Top image via Cool3C.