need new tool boxes/best bang for the buck

I have had this one now for a couple of years along with the bottom that is listed as its accessory.and I am still impressed at how it is holding up. It has seen a lot of movement around the shop but I can't say for sure how it would hold up being moved around on a trailer and such. It locks up tight and the drawers with he roller bearings are holding up so much better than my Craftsman box.
http://www.homedepot.com/p/t/203469...1vZc2gkZrdZ1z115k9&R=203469292#specifications