I have the Hitchgate. Positives are you don't have to crawl under the truck to access a spare covered in mud and dirt, and the Hitchgate also can allow you to stow other stuff (extra fuel and/or water, hi-lift, shovel, Maxtrax, and Trasharoo in my case). The Hitchgate is also prefect for hanging stuff on when camping.
The downside is that you have to swing it open each and every time you stop and want to access the camper. You can't stealth camp with the Hitchgate on, as you can't swing it open from inside the camper.
I leave mine on most of the time, though usually remove it in the winter when I run my studded winter tires..and then keep my winter spare under the truck.