I have the Pullrite slider also and feel it is worth the price. The weight of the hitch was mentioned and it is quite heavy but it breaks down into smaller units which make it more manageable. Previous posts have mentioned the practice of pulling the pins on the hitch mounts, leaving the hitch attached to the pin on the 5er and letting the hitch hang by the pin. I have never tried this and I don't know if the pin was designed to have a couple hundred pounds of hitch hanging from it. Really like the hitch, though.
I also pull with a GM sb cc and would not even imagine needing a slider hitch of any type. I have seen posts here where guys have actually caused damage to their tailgates because of the extended pin/slider combination.
Obviously, the clearances are dependent on your 5er and king pin length, but with mine, a slider would be wasted money.