I've been running the 21K Hijacker autoslide for just over a year now. I cant comment on the pullrite version, but the Demco has worked well for me. If you are running a mor/ryde pinbox, then you need the capture plate for the demco, but otherwise for a standard pinbox no capture plate is needed. I believe for pullrite you need a capture plate regardless of the pinbox used? I also believe the demco can be had for less $$$ online as well.
I have no experience with the Anderson, other than to say, you have to install an adapter on the pinbox to use the Anderson. Not a biggie, but I lump it into the same category as a capture plate for the pullrite and demco (in certain cases). Normally not a big deal, unless you need someone else to tow your 5th somewhere, you have to remove some "stuff". And, before anyone chastises me, its just a "consideration". Not saying its bad or good.