1. Maximum Power Dissipation (Power - Max): The SBCP56 is rated at 1.5W, more than double the 725mW of the BCP56. This is not merely a numerical increase. The SBCP56 features lower thermal resistance, resulting in a lower junction temperature rise under identical operating conditions or the ability to handle higher continuous collector current with the same heatsinking. When substituting, the existing PCB's thermal capability must be re-evaluated to determine if it is underutilized or insufficient. 2. DC Current Gain (hFE Min): Under specified test conditions, the SBCP56 has a minimum gain of 100, significantly higher than the BCP56's 63. This indicates the SBCP56 offers higher current drive efficiency. It can deliver higher collector current for the same base drive, or require less drive current to achieve the same output, which can simplify the preceding driver stage and reduce power consumption. 3. Transition Frequency (Frequency - Transition): The SBCP56 is rated at 130MHz, compared to 100MHz for the BCP56. The higher fT of the SBCP56 translates to faster switching speed and lower switching losses, providing superior performance in applications requiring higher switching frequencies, such as PWM control. 4. Price: The SBCP56 ($0.710) is approximately 65% more expensive than the BCP56 ($0.430). This is the direct cost of the performance improvements. A trade-off must be made between system performance, reliability requirements, and overall cost.