I also have the M1 account (Thanks Slava!) and am extremely happy with it. We have paid down nearly $15,000 in debt since getting it last fall, while not really changing our spending habits. Those habits, however, have always been fairly conservative though....which I think is the key with this type of account.
I think the best advice I could give is to sit down with an expert on the product for an hour or two. My wife was really skeptical about the whole thing at first, but after hearing the details about how it works and why it makes such a difference every month, we both agreed it was a no-brainer.
You should also be prepared to throw up in your mouth after you use a bank machine for the first time and see your account balance is $ -150,000.