S-AFC I vs S-AFC II

[1slowdsm]

So I'll be getting an afc pretty soon and I just wanted to know whats the differences between the two. I know that the afc II has a few more functions, but I dont really know how much of a difference it'll make. My brother in law just got a power fc for his car and he said that he'll give me his afc I if I wanted it. If the afc II is much better, than I'll think about upgrading the afc I sometime next spring.