Hi all,
I'm keen on all leaves, but I'm not sure that IAL are much better than Oak, Magnolia or Beech leaves. My personal experience is that Alder cones (Alnus cordata/incana/glutinosa) are a better water conditioner for eggs and fry than either IAL or Oak leaves/bark, although these would be my next choice.
At the moment my favoured leaf for bigger tanks is Loquat (Eriobotrya japonica), as these are a good colour and very persistent, I'm using Camellia leaves in the smaller tanks.
cheers Darrel