This was a helpful thread to read through as we are doing our build list as well. From all of the opinions and information given here, we are satisfied with our decision to have the insulation and spray foam package.
We intend on using the trailer in what could be extremes in temperature, so having this protection will not only help with the temp variables, but also mitigate reflected heat from the pavement when I travel down south. There is also the noise factor to consider, as well as insulation of the water tanks. All positives in my book!