When you can afford it, spring for the Basis belt. Their newest belts are extremely precisely ground to an even thickness and sound much better than their old belts. I doubt that a non OEM belt would come close. Two different friends heard both an upgrade to the belt and the installation of the $5,000 motor control unit, I believe on a Basis 2500, and actually thought the belt made a more substantial difference.
Although the 1400 is the cheapest model in the lineup, the critical parts are actually manufactured to extremely close tolerances, like all Basis turntables. The benefits of a similarly manufactured belt will be heard on this table.