Yes I am currently on Bittrex with 98% of my holdings. That said, I had an issue with Poloniex over a month ago and they still have not so much as taken a glance at my support ticket. I transferred out SIA coin and provided them with the correct address. Their records show an "error" however my SIA never landed where it was sent and has not be put back on my Poloniex account either. Essentially, they have stolen my SIA coin and not addressed my support ticket in over a month. Alternately, Bittrex is always responsive on Twitter and I have never had any issue or incident. So I do my best to stick to that exchange for trades. I agree that the US is flailing to figure out how they can get a piece of the action, and I assure you they will figure it out. They are already starting to address certain ICO's... HODL on, it's going to be a bumpy ride and an amazing adventure!