Hmm tough to say because, as far as Zelda locations go, they're rather different.
In Twilight Princess you have this more open, kind of empty, forest that is quite linear in design (leading up to the temple) while in Skyward Sword It's more compact and content filled. The navigation is quite different too, TP's version is split up into several parts, but it's all rather a straightforward line to your destination. In SS It's more so set out like a puzzle (well the first section anyway); it's quite confusing in design and it may look rather simple to navigate, but areas are disconnected so to say. I guess it depends what you prefer though, if you like a more open simple design then it's Twilight Princess, if you like the puzzle approach then it's Skyward Sword.
Personally I prefer Faron Woods from TP, but not because of its design. Truth be told, I love the setting; it's very spiritual like, creepy, mysterious, gloomy, picturesque all in one. SS just seemed to be bright and colourful, it emphasised that feeling of a living breathing forest better than TP, but to me it just didn't create that same lost-in-a-forest-like atmosphere. Also I loved the Faron theme in Twilight Princess - one of my favourite themes in the game.