Specs wise they are nearly 100% identical. The price on Amazon is the same for both. Is there any reason to purchase one over the other? I don't care about the docking keyboard on TF300.
If you didn't get one or the other, I would pick the MeMo due to the micro-usb charging port (vs the proprietary charging port of the TF300) and the better speaker placement.
Some reviews point to better build quality with less chassis flex as well...