Thanks for the input! We're integrating more brokerages as we go. We've been swamped with requests, so any indications on your favorite brokerages would help us choose. Right now we've queued up Interactive Brokers, OptionsHouse, TradeKing and Wealthfront. Also have requests for Betterment, Loyal3 and Motif. If there are any more we should add to the list we'd love to hear it.
