The short version is its refusal to box things means that you have to have the connection, the statement, and the cursor all as local variables in the same lexical scope (you almost always want to abstract away the statement and cursor), and it's use of trait objects for serialization and deserialization. I might go into it briefly in my talk, but I don't like to rag on other people's work so I probably won't say much on it.

(Sorry for the double post, I think I replied to my own comment and not yours!)