So with today's market hopefully I can get the 2.5% no cost with Alyson, if not I think the Third Federal mentioned by qwerty might be a better product for me. The MS IO loan is at 1.9% and is variable month to month (I think anytime Fed's raise rate, the LIBOR will mirror). So it takes just 2 more rate hikes (unlikely in 2016 so far) for the IO loan to be at the same interest rate as my current 5/1 ARM. Yes it's nice to have a lower interest payment when I reduce principal with the IO product, and I believe having a lower monthly required payment for 10 years is nice in case of income loss (sickness, unemployment). The Third Federal is only slightly higher in interest and locked for 3 years and the re-lock for a flat fee is a good option. So theoretically you can keep re-locking every 3 years or so to guard against high interest.
Third Federal's interest of 2.44% to make it a low cost loan seems rather high. Break even for paying the $3000 in cost is about 20 months. I wonder if there's a catch... none of the 3/1 ARMs from Zillow are even close to the 1.99 rate.