The STM32F401CCU6 module ("Black Pill") is a direct upgrade to the older STM32F103C8T6 module ("Blue Pill"), offering significantly better performance, more memory, and enhanced power efficiency.

Key Differences in Modules

• Performance and Math: The most significant difference is the F401's Cortex-M4 core with a Floating Point Unit (FPU) and DSP instructions, which allows it to handle complex math, audio processing, and motor control tasks much faster than the M3-based F103.
• Memory Resources: The F401 board provides more than triple the SRAM and significantly more Flash memory (256 KB vs. 64 KB), essential for larger and more feature-rich projects.
• Power Efficiency: The F401 is built on a more modern manufacturing process, making it more power-efficient than the F103, which is beneficial for battery-powered applications.
• Module Design: The F401 boards typically feature a modern USB Type-C connector, compared to the F103's Micro-USB. Many F401 boards also include an extra user button and an SPI flash memory footprint on the underside for expansion.
• Programming: Both boards can be programmed using SWD (Single Wire Debug) with an external programmer (like an ST-Link) or via the built-in USB bootloader (DFU mode). The F401's bootloader mode is often easier to access using the two onboard buttons (Boot0 and Reset). 

For new projects, the STM32F401CCU6 module is generally recommended due to its superior specifications and modern design, all while remaining highly affordable. The STM32F103C8T6 module is best suited for simple, cost-sensitive projects or as a basic learning platform.