I’ve gotten the signup credits from both accounts, and referral credits work well to. There’s one interesting twist to the credits you receive on the investment account. It appears they deposit $100 in your account, and then use it to automatically purchase stock. You’re still getting the $100, it just works differently than it had been and I originally expected.
It even seems I’m getting the $100 in stock commission free, they’re not recapturing cash that way, though I haven’t verified I’m getting the best possible price on the shares at the time of the transaction [however I’ve had gains in the account, not losses, not I’m actually coming out ahead so far].