Got my Kup yesterday. I really like it. As others have mentioned, it's very solid. I really hated how Bumblebee and Megatron both had parts that seem to be there because there was no other place for it (The turret for Megatron and rollcage for Bumblebee).
I don't collect O-Rings anymore, so I put my SDCC Slaughter on it.
Here's some pics.
Bot mode:
Alt mode:
You can put the 25th Slaughter baton on the back as well. I also made a peg in the back to hold my custom Slaughter's ditty bag on the back.