I'm planning to send my Auntie and Uncle this year a gift card this year. They live close to two towns and tend to go to one more where they also do their food shopping at Sainsburys. For this reason I thought a voucher for Sainsburys might be more practical. However, I think an M&S gift card would be more special but it means them going out of their way/delaying spending it in the other town.
Which would you buy?