The extra tray is great. If I am using 2 sizes of dies, especially ones that use different layers of shims, I just remove the tray and used the second tray. I can use an extra thick die in one, and a thinner full sized die in the other without having to remove all the layers for each cut.
I love this sliding tray, I can load it up with my dies and just run them once to save time in my crafting or quilting. I'm happy that I purchased this extended sliding tray. This is an investment that's worth it.