On deck will do the lowest rates, I have clients funded 12 month 1.20s with no fees with Ondeck, however those are unusual situations where we have came to special arrangements because that's lower than their normal buy rates. And those were super clean files the merchant could have got bank loan but didn't want to be bothered with all the paperwork, on decks quick and simple streamlined process made it worth the extra cost to the merchant.
IOU has an actual 12.99% APR loan, but it has fees that raise the actual cost.
Keep in mind that very few merchants will qualify for either of those programs.
If you are going to mention your rock bottom rates, I would always do so with a disclaimer-
"well Mr Business Owner since you insist on know what is the best possible rate we can do, its 12.99% however very few of my clients qualify for that program, send in your paperwork and I will get your the lowest rate that you qualify for"

If someone tells you they got a 10% rate 9/10 times they have it confused with their holdback %. You'd be amazed how many business owners that take out cash advances still do not understand what a cash advance is, and they think the holdback % is the cost of the money