I have used dog boxes for years and recently installed a topper (used) and built storage box in bed. I am currently using Vari-kennel type plastic boxes but intend to buy a trailer when I can afford it. The nice thing about a topper is that you can carry a bed full of cargo which is protected from the elements and can be locked up. This is handy if you travel where you are staying multiple days. If all of your dog transport is day trips then the box works fine. I personally feel that the topper with trailer and plastic boxes gives you the best combination. The trailer is nice when you are using more that two or three dogs which makes getting them in and out of the pickup difficult. I have never used the dog topper with compartments but it seems like it might be a good compromise. I camp out of the topper also so that option doesn't work for me.