There is a subtly different feel to the two decks. Faeries' Oracle seems more ethereal and otherworldly, whereas the Heart of Faerie seems more earthy, or anchored more obviously to the natural world. A large part of this is that the images in the Faeries' Oracle mostly show individual faeries or groups of faeries (Froud likes to draw them piled on top of each other, as if the world absolutely teems with faerie of all types) in a dark, empty or indistinct background. This lack of context lends a feeling of separation. Also, in Faeries' Oracle, there is a whole class of faeries Froud calls 'Singers', which are abstract beings of radiant light and energy. (These are actually my favourite images of faerie and I wish he would do a whole Singer deck!).
The Heart of Faerie Oracle, on the other hand, seems to me to show more faerie against a natural background of trees, leaves, twigs, flowers, starry skies. Even those cards with an indistinct dark background somehow make you feel it is the night sky as seen from earth, rather than a sort of cosmic blackness. Also, it seems to me, though I've done no counting and it may just be my perception, that there are more humanoid faerie in Heart of Faerie Oracle than in Faeries' Oracle. These factors make Heart of Faerie feel more earthy to me than Froud's first oracle. When I first got the two decks, having done no work at all with faerie in any capacity, oracle decks or otherwise, I felt more comfortable looking at the Heart of Faerie, and that's why I decided to put it aside and work with the Faeries' Oracle instead. It seemed best, and I'm glad I did it.
Some people feel that the two decks don't work together very well and like to keep them separate. Others shuffle the two packs together and feel they harmonize very well. I quite enjoy shuffling the two packs together, though it must be said that because the Heart of Faerie cards are very slightly larger than the Faeries' Oracle, when you cut the deck you will cut to a Heart of Faerie card nearly every time. People have theories about how this shows the Faerie Oracle faeries are more shy than the Heart of Faerie or that they don't like being mixed in, but actually it just shows that when you grab cards by their edges, the edges you grab will be the edges of the bigger cards. You can't cut to a card whose edges you can't touch. I have briefly considered trying to trim the Heart of Faerie, but it's a fool's errand as the difference in size is so miniscule that trimming would only make matters worse, so best to just leave it. Chronata at AT says that if you shuffle and cut the deck with cards facing up, it is more randomized. I haven't tried that yet.
To give you an example of what I feel is the fundamental difference in these two decks, I've chosen two parallel pairs: The Green Woman and the Lord.
|Faeries' Oracle, Froud (2001)|
Now compare those images to their equivalents in the Heart of Faerie Oracle. You get the same earth-connection and confidence in the Green Woman, the same pathos and delicacy from the Lord of the Forest, but check out the difference in the tone and feel:
|Heart of Faerie Oracle, Froud 2010|
It's not entirely accurate to say that the Heart of Faerie Oracle seems more 'human' than the Faeries' Oracle. That's not it exactly. The only word I can think of is that it is more 'earthy'. I do not think that one is better than the other. I like them both. If you are interested in owning faerie decks, I would say these two are essential for your collection. I might even go so far as to say, these could be the only faerie oracles you would ever need. (Until Brian Froud publishes another one!)