How much more interest is a 30 year loan worth today?

[Chris Lohmeier]

I have a very specific situation but also a broad question.  

I have a property under contract with a closing date that gives me plenty of time to search around for the best mortgage. This is a good SFR, a great deal, and I have no intentions of doing anything other than holding it at this point.

I have three leading contenders.  

My usual Credit Union: I've already been approved at their standard terms of 5.5%, 20 year Am with a 5 year balloon.  

A mortgage broke: with terms of 5.625%, 1.875% in points, 30 year conventional with no balloon.

Small town bank in my area: Not final yet, but looking like 4.75-5.25%, 20 year Am with a 5 year balloon.

The broker will have quite a bit higher closing cost with a conventional appraisal whereas the credit union and bank will do them in-house. 

So situational question. Is there any reason not to pay more up front for a higher rate, but be guaranteed that the rate will never increase?

Also, are others seeing rates that are much better than this for 20% down?

Broader question. At what rate differential would you not take the 30 year loan?

Thanks for any advice.