If a person will earn 30% of their contributions when they decide to withdraw, this means they will receive around $1,950 from their Roth IRA, but $5,850 from their Roth TSP. So, the earning from Roth TSP is three times as much as that of Roth IRA! The Roth thrift savings plan can, therefore, be more profitable for someone whose income allows them to reach the higher annual contribution limit.