The basic summary is this:

If you have a Mod 3 or older (if it's eligible to upgrade) then it's worth it. If you have a regular Mod 4, it's not worth it. I did have a Mod 3, and I do have a regular (pre eco-baffle) Mod 4. I won't be upgrading the Mod 4. Not enough evolutionary change or improvement to make it worth the cost to go from Mod 4 to the eco baffles.