Window Heat Loss Protection

What is more effective at preventing heat loss in the home through the window?
3M Window Film
Cellular Blinds
Any pros and cons? Personal experience?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.