I don't understand.
Meh, I don't really care.
Nice, but not for me.
I'd use this if it was free.
Great! I'd pay USD 5 monthly for it.
Must have! I'd pay USD 20 monthly for it.
Unload (instantly sell received bitcoins)
Best Buy (rebuy bitcoins at the exchange with lowest price)
HD-wallets (support for modern wallets like Electrum, Mycelium, GreenAddress; also called BIP32)
OAuth (connect with exchange with a few clicks instead of API key creation/copying)
Below-market-price Orders (only rebuy when BTC price falls)
Additional Payment Data (eg. get fiat price from 3rd party providers)