Question about Angel Shares.

I've read some of this thread, but it's getting pretty long... I apologize if this has been asked already.

With this whole donate-to-recieve Angel Shares thing, if there are only 5000 AGS for PTS per day, that means that it's a crap-shoot how many AGS I'll get for a given PTS donation? Why don't I just donate .0001 PTS per day?

Also, is there any advantage to holding AGS vs. PTS? I mean, I can at least trade PTS on an exchange.