Thanks JL for your opinion.
It seems that professors that we have contacted like the the board with a built-in FTDI231XS, it makes a less of chance for students to lose the FTDI cable.
So we will probably do the $25 option first. May only charge members for $19 if more people and schools are interested. Once we start to make it, we will post a link here for anyone to place an order.
Wayne