We just used the factory 1.9% - it was relatively painless process - just filled out some paperwork at the dealer. Our credit union couldn't touch the rate. We had a large downpayment from a totaled vehicle, and our credit is very good. It can be hard for banks to go as low as the subsidized 'teaser' rates the factory offers.
We did the 1.9% though Hyundai. It was available for up to, I believe, five years and we took it for four. Shockingly, our whole experience was excellent. I generally hate the finance department but the one we dealt with was amazing, he didn't try to sell us anything extra and it all went super fast.
Mine was a little longer. They really, really, pushed the extended warranty. I believe that they did so because the car I traded was still covered by one so they wouldnt take no for an answer. Ultimately, they won, I bought the extended warranty....at a price about 2.75 times less than they came in with. In addition, they gave me an out the door price but it slightly adjusted toward the end because of gap insurance...which I didn't need because of my down payment. Just a note if you plan on financing for 5 years, I would recommend calling your own car insurance company and asking them to price you gap insurance. It should be roughly the same amount the dealer/Hyundai is offering but the difference is you will have the flexibility to remove it from your policy and are not locked in on it for the full 5 years you are paying off the car.
I used Hyundai's 1.9% for 5 years. I put down 20%. Plan to pay off early. Financing department was quick and easy. My investments earn me more than 1.9% so why pay cash. I'm only paying off early because I'll be retiring.