how is it a better deal? If you don't have the Verizon payment plan the line access is $40 instead of $20.
the Verizon one is $5 a month, plus I traded in my old phone, seems like the same deal?
This is a DPP, not a service contract.
For example, I'm on the new Unlimited Plan. My line access fee remains $20 either way - it doesn't matter if I get the phone at $5/mo with bill credit through Verizon or $5.99/mo through Best Buy.
Verizon deal isn't good
if you don't plan on keeping the phone for 24 months. For example, if you want to get a new phone via DPP pricing in six months, here's how the math works:
With Verizon's $5/mo with bill credit, after six months, $306 would be due in (as in the DPP would need to be paid off) before you could start another DPP plan with that line.
With Best Buy's $5.99/mo, after six months, $107.82 would be due before you could start another DPP plan with that line.
Verizon's deal is better if you plan on sticking around for 24 months and you don't think you'll need to buy a new phone on DPP on that line. You'll save $23.76 over the Best Buy deal.