The DJI hardshell backpack retails for $149. However, a quick Ebay search shows many similar looking hardshell backpacks for less - some as low as $65 - that appear to be practically the same except a picture of a quad replaces the DJI logo. Has anyone been able to physically compare the official DJI backpack to these, I assume, knock-offs? Is there a legitimate reason to go ahead and spend the $149???