If I get 3% or better on financing I always go that route. I go a little higher on investment properties but someone else is paying my bills for those. It's all math, and if the numbers work, they work. Cash is fine too and not all "investment" money is in 401K or IRA's sometimes a straight brokerage account is the way to go, not everything is tax advantaged once you reach a certain point. Make your cash work for you if you can. Inflation is about 3% so if you borrow at that rate or below you should break even or better. That frees up your cash to be used other places that may pay you a pretty good return. It's all a risk of course but such is life.
Thats what I always said is anything around 3-4% or better is free money, people dont understand that because of inflation. Anything under 3 you are technically making money, even with a $700 fee added in. I give basic finance classes all the time to the work force here granted i am no wizard. But it blows my mind the amount of misinformation and though processes out there, and you are talking about everybody from the age of 20 through 60. Actually found the people in the 50s sort of age tend to be the most backwards in terms of having no retirement and have basic financial issues. Need to bring some basic econ classes back to HS kids.