LPC2148 is a 32 bit 60MIPS MCU with 32K RAM, and Espardino supports microSD/SDHC cards. All the calculations on my code take just 125 microsecond on that MCU. It means I read the line 4 times in every one milimeter. I think a 8 bit 20 MIPS MCU can run the same code within 750 microsecond. Besides I log some important data in the 32K of RAM without effecting the normal operation of the robot and then dump it to a microSD card and then analyze it in the computer. This is very useful for debugging and finding out some bugs.
I burnt one of the motor drivers when the motor got stalled last week and I could easily replace it with a new one. So, Orangutan SVP-1284 Robot Controller is not suitable for me because I am not able to solder some SMD parts. When they are seperated parts, I also can replace the motor drivers with which are more powerful than them if I need . Besides I can place the parts on the body more properly than a single big package.
Espardino + two TB6612FNG carrier + pushbutton cost $75, but an Orangutan SVP-1284 Robot Controller costs $90. Everytime I need more power at low cost
I think you could probably replace two MCUs on your controller with a powerful MCU like based on ARM7