Brother MFC L2750DW XL is actually the same printer as Brother MFC L2750DW. They have the same functions and use same toner cartridges. The only difference is that new Brother MFC L2750DW XL printer comes with a starter cartridge inside as well as one genuine high yield TN760 and one genuine super high yield TN770 toner in box. While Brother MFC L2750DW printer only comes with a starter cartridge inside.
Therefore, when the starter cartridge runs out of toner, you can replace it with TN760 or TN770 toner. Generally, super high yield toner TN770 will be more cost-effective because the cost per page is lower than that of Brother TN760 toner cartridge. But if you don’t have enough budget for TN770 toner, you can order TN730 or TN760.