The ending of the first "season" of Princess Tutu was the strongest part of the anime for me. The second season has a rather dull middle part, a series of three or four episodes that aren't bad, but don't do anything and feel like silly padding at a point where there no longer should be padding, and then it gets pretty creepy. I still am, and most likely will remain forevermore, unable to ascertain what to make of it as a whole. That's an achievement all of its own - It's Schrödinger's anime for me. I laughed at Ahiru's hijinks, I got emotionally invested in Rue's story, and I really ended up liking Edel even though that probably barely seems possible from where you're standing at the moment.
The anime generates an absolutely fantastic, dreamlike fairy tale atmosphere. All of that was good, but if you'd ask me if it was time well spent watching, then I have only two answers. Yes, and no. Everything was both meaningful and pointless, a story about storytelling and a story told, a fantastic piece of art and the lowest folk tale. Well, the most flowery nonsense to post won't change that I can't really put into words what Princess Tutu is.
I fond every single part of Princess Tutu good, sometimes even great. It's the sum total of everything that exists in this state of being filled with meaning while being completely pointless at the same time. I think that's enough, I wonder if you'll end up watching it all and will have a different opinion. Time will tell.
I went over her list of credits twice, there's nothing on it that I've seen in the original except her being Envy in FMA: Brotherhood, but that's definitely not what I'm thinking about. Whatever it is, it's just a nagging feeling that I've heard her before, when I simply didn't.
First, I have no idea how I got the episode numbers wrong, I now watched 11 and 12 - the suspicion is confirmed, not that it was much of one.
Mild spoilers:
Since the show has hinted at there being at least one more person from Earth somewhere with Hitomi finding a music CD at a market, I've been thinking about who that could be and if that will actually matter. I can't really come up with any good ideas so far, and none of the characters introduced so far could be it. No one except the Emperor of Zaibach, at least, because he just appears on a viewscreen and could look like anyone.
It's also of course possible that the disc was just transported to Gaia in some fashion, without anyone else. Gotta say I'll be disappointed if that doesn't come up again.