If the service manager at your dealer is calling the Pullrite hitch junk, I would have serious concerns about his/her credibility. For them to have the opinion that you don't need a slider is one thing but the Pullrite is a quality product. It's made here is the USA and their customer support is awesome. Your dealer will make more money from you selling/installing the generic hitch they want you to have rather than ordering the Pullrite.
Kevin & Janine
2006 Dodge 2500 Megacab CTD 2WD
2012 Palomino Sabre 32RCTS
Pullrite Superglide 16K Hitch