I actually preordered both decks at the same time, so I have both of them! They're both technically decks about the fey but they're very different takes on it. Honestly, I think they're very different decks and you should go with the one that you feel drawn to or think suits you best! Here are my thoughts, however, in case they're of any help.
The Tarot of the Hidden Realm is admittedly my favourite. It's very focused on the characters in the cards and who they are. Personally, I wouldn't be able to read this deck if I didn't view it as establishing a relationship with those characters and getting to know them. It's a very hard deck to approach in any other way, at least as far as I've found. It's not very WCS based, especially in the art, so if you prefer that then I would avoid this deck.
There's so much personality and life in these cards though, that I find myself thinking of them as being almost sentient. This is not a sentiment I am especially prone to -- I'm often found telling people, "Your cards are just paper and ink!" and yet....there's something in the Hidden Realm cards that just seems "more".
If you're wanting a deck you can really settle in with and get to know on a deep level, I think this would be a great choice for that kind of thing. Or at least it has been for me.
The Victorian Fairy Tarot on the other hand, while not being a straight WCS clone, is going to feel much more familiar if that's what you're used to working with and what you're looking for. It's got very pretty art, but...I have to admit, I kind of wish I hadn't gotten it at the same time as the Hidden Realm deck.
Seriously, it's such a lovely deck, but next to the Hidden Realm it just seems flat and lifeless. Which isn't fair to it -- it isn't meant to be the same kind of deck. The art is storybook and that's kind of the point. (It actually kind of feels like a deck of bedtime stories)
It's just a much more standard feeling deck, which isn't a bad thing! But as it turns out I was really wanting something interesting and something I could experiment with and form a relationship with and the Hidden Realms did that for me. I'm sure the Victorian Fairy Tarot will have its moment for me later though.