I watched the first two seasons and got bored with the third. Now that it's done I'm playing with the idea of picking it up again and going all the way through, from the start.

Does the show wrap up its mysteries? Do you get the sense that things were planned all along, or does it feel like they made stuff up as they went, a la Battlestar Galactica? Also, was the first bit of season three really worse than the rest of the show like it felt? Does it get better than that?