I used the pear concentrate to make a pear cider. I had used the 96oz to make a 3 gallon batch (that crept up to 4 gallons). I added several cups of sugar and water until I reached 3 (4) gallons and an OG of 1.060. I came out pretty good. It was lacking in pear flavor so I added pear extract to bump it up... but that is a pear issue, not a Vintner's Harvest issue.
I would say your only drawback would be cost. 5 gallons of juice at Costco is pretty cheap. I don't know what the apple juice concentrate costs, but the pear was like $36.