Christmas Giveaways

I'm torn between using custom mugs or USB drives for my client's giveaway this Christmas. He wanted to have a raffle for iPhones too but I said we can do that next year, around February in time for the new product launch. I will be designing the logos/graphics on all his giveaways so he told me to choose to make it easy for me. I know the mug should be easy but I still think USB drives will be much more appreciated by his customers. It's more pricey than the mug but definitely more useful.