Hi Marijn,
I finally got around to implementing a proper serialisation for arrays, both as query text and as prepared-query parameters (which requires two wildly different formats --- ARRAY[E'a', E'b'] versus {"a", "b"}). They should now Just Work. Also added a :[] sql-op, so you can do (:[] 'myarr 1) and it'll expand to (myarr)[1] -- including superfluous parentheses, since in a lot of situations they are required.
This is extremely great, thanks a million!
-Daniel