Prefer them to the MMs when there's a choice. My machine crashed since I typed it in. Still in, basho. When Tom comes back, repeat your question anyway. But, I think ARCA had a system problem.
Chances are probably a lot better here than on the web with discont brokers.
It would be nice to have a separate ARCA button. That would work the same. I asked a question about unusual after hours trades and then crashed. When I right-click on the button, I don't have an ARCA option to change to. I crashed after asking a question too.