My own experience with letting a vendor have access to my account was all bad. Once I allowed these charges to take place, the bank would continue to honor them evn though I told them not to pay it. (billing dispute with a vendor )
I realized at that point that once the electronic transfer authorization was made my relationship changed from being a bank customer to an outsider to my very account. And even when I stopped putting money in, even when I warned the vendor I wanted them to stop trying to take money from my account, the bank continually accepted them even with a negative balance.
Since that time I have never allowed any electronic debit to my account for any reason. Even for a service or a product I really wanted if they demanded electronic funds transfer, I would just not buy or go elsewhere, even at the risk of higher costs just to keep the cheating bastards away from my money.
And to our smug Euro and Commonwealth comrades: It's cool to be smug about electronic stuff, but what you fail to realize and may well never realize at least we still have this freedom and choose not to let a bunch of criminals and criminal enterprises access to our accounts. We know just as welll as you do how to operate an electronic account and yet choose not to.
It's called freedom. You should try it.
Integrity will trump convenience everytime