So you still want to know the difference between the TAF and the TSLF? Over at Interfluidity, "livingstone guy" explains:
The new repo line you talk about is nothing more than the TAF for the brokers who dont have access to the TAF. Essentially, a Merrill wants to have the same access to liquidity as JPMorgan but doesn’t have it in the current framework of TAF which is only available to depositories. The new repo line just makes the same facility available to Merrill.
Only fair, really.
Update: Interfluidity’s Steve Waldman emails to say that the comment was about a repo line which actually predates the TSLF. But what’s true of the repo line seems to be true of the TSLF as well: it’s available to "primary dealers" and not just "depository institutions".