Oh man, now you've done it - you will get every opinion going on this one
Take a step back would be my advice...
1. You clearly wanted a tablet & not a quasi laptop or you would have bought the TF in the first place, I guess?
2. The MeMo is the newest device released by Asus & has advantages over the TF300 - microUSB charging, USB OTG, Gorilla Glass, designed/released with Jelly Bean & as the newest device from Asus you could expect updates to continue for at least 12 months longer than the TF300 (or TF700)
3. If your budget is $300, then stick to it - certainly don't blow it on the TF700 which is a lot more & will give you no more functionality than the MeMo
In short, I think you bought the right device at the right price. The BT keyboard case accessory will be available soon - or just get a $20-30 BT keyboard if you really want a physical device to type on. But I have never used a physical keyboard on any of my tablet devices - every word I have ever typed on this forum (all the guides included) have been done on soft (screen) keyboards.
That's my take on it