I invest on TDAmeritrade. My experience so far has been only positive. They don't charge any commissions and your selection of stocks is significantly larger than EE. I have not come across a stock that I couldn't find on TDA.
The drawbacks are threefold from my perspective:
That said, there are multiple other advantages like inter alia being able to set limit orders over EE that is a more vanilla offering. I'd definitely recommend anyone to open an account with TDA and experience it for themselves.