Dunno about using OEC - I had major issues just trying to communicate with them when I wanted to open an account - scores of unanswered e-mails and so on. Their software looks terrific but their erratic approach to communication put me off before I even started with them. FWIW when I did manage to get through to them they seemed really nice, the main guy even used to call me (and I live in Australia so the timing was not always real good) but I need reliable comm's to any broker.
For those who are not experiencing problems, are you using the OEC Trader lastest version or another third party software? I dont experience much problem until lately when they upgraded the software.