Don't forget that those low or zero interest cards are just waiting for a reason to slam you with 28% interest. We transfered a bunch several years ago for all of the reasons stated above. For some reason, Citibank applied one of our payments to somebody else's account, thus we "missed" a payment. The next day, we receive an express letter stating blah, blah, blah, we are jacking up your interest to 28% and assessing fees, blah, blah, please send us $400 PLUS the monthly minimum to get your account active again.
We got everything straightened out eventually, but we spent several stressed out hours on the phone. Plus, we were scared out of our mind that we really would accidentally miss a payment. We simply could not afford the minimum payments if the interest jumped to 28%.
If you play with snakes, they eventually will bite you. Don't try to borrow to get out of debt, get on a budget and pay off your debts.
Seriously, get The Total Money Makeover and you will never regret it.