I should mention I am not associated with Jaxx at all. I am not an expert either.
As far as I know, Jaxx is a wallet for storing multiple types of cryptocurrencies and tokens. The currently supported ones are Bitcoin, Litecoin, Eth, Dao, Dash, Etc, Rep, Zec, Rsk. These can all be found in the settings of the Jaxx app.
Jaxx makes it possible to backup multiple wallets using a single backup phrase. It somehow uses the BIP32 technology to accomplish this. I do not understand the technological specifics of it.
I have tested out Jaxx with some Litecoins, and it works well for me. I do not vouch for the security of the platform though. But, it seems like quite a few people like it and feel that it is secure. At the least, it is a real company with a real face behind the product. Anthony Di Iorio is the CEO.