On a 2 year contract you have 14 days from VZ to "try out" your new device and return it. VZ charges a $35 restocking fee if you simply return it. Best Buy does not! Best Buy has a 30 day return policy, however if you return the phone after 14 days you are subject to an ETF unless you exchange the phone for another device. Last year I exchanged my phone 4 times with no hassles, penalties or fees at BB. If you are committed to a new device, but can't decide on which one to go with Best Buy is the clear choice. They will also price match if you are paying retail for the phone.
Some other thoughts: If you are a Reward Zone Silver member your return policy is 60 days.
BB Black Tie protection is $10 per month, but it has a $0 deductible and unlimited use over the 2 year period. It does not cover lost or stolen, but it does cover everything else. VZ charges $7 per month with a $100 deductible and you get a refurb.