To find a good partner for peanut butter, we tested four preserves from the top-selling brand (Smucker’s) in the top-selling flavor (strawberry). The regular, Low Sugar, and Simply Fruit products were all very good. The regular and Simply Fruit were especially sweet; Low Sugar was more tart, with lots of strawberry flavor. Sugar Free with Splenda was good but had a lingering artificial-sweetener flavor and wasn’t much like real strawberry. Its main plus: 10 calories per tablespoon and no sugar, compared with 50 calories and 12 grams of sugar for regular Smucker’s. The preserves cost from 13 cents per tablespoon (Low Sugar) to 18 cents (Simply Fruit).