Yes SW, and yes you must convert them. Depending on the custodian, they may charge you a small fee for the conversion.
The harder question is whether the B shares can be transferred in kind. Theoretically they can be, but I tried every custodian in America and none would take them. So if you ever have to switch custodians, you might have to convert and lose the super votes.
Micro, that's always been my understanding too, and I've always converted soon after receiving so I'd have the flexibility to sell if/when I wanted to. However, I've always been confused by the fact that ATROB does appear to trade, based on info shown on various quote systems...e.g., Schwab and Yahoo shows it traded 300 shares this morning at $62.40! How does that happen? I'd certainly be willing to part with some of the class A shares today at that price!! GLTA