Fucking addicting.
I really haven't done much yet, just beat the Snow Temple and have to go back to the Spirit Tower to get the railmap for the next area, but it is definitely a major improvement over PH.
I do like the traveling by trains, though the goddamn fucking demonic bomb trains that if they hit you it's game over and you can't kill them only slow them down piss me off.. and having to readjust your route so you don't get hit by them.
Though the fucking one that's on crack and turns around on the tracks and is like a heat sinking train of death that follows you and then boom is really cheap.
I love how the Spirit Tower is not repetitive at all like Temple of the Ocean King.
Sure you have to go back after each dungeon to get a new map, but you can skip previous floors, and no time limit, and having Zelda in there with you is a big help.
And it's actually fun figuring out all the puzzles.
A lot of sidequests too which is great, dropping off passengers, delivering freight, rabbitland rescue, monster kill-em-all. I particularly love the stamp book, wish there were more stamps to get though.
I also like playing the songs via the spirit flute, though it can take me a few times doing the duet with the Lokomo's to get to each temple.
Also rolling by double tapping the screen, although I had no problems by circling on the edge of the screen in PH, apparently some people did.
Overall, one of the better hand-held Zelda's imo, and a vast improvement over PH.