I bought Guardian Signs last week and I thought I'd share my opinions on this amazing game.
Positives
Free Flying: This is a feature I've wanted since my very first Pokemon game. It was done really well, something I hope we see more of in future games.
Ukelele Pichu: Although I prefer the feature in Ranger 2 when you can change between partners, how can you not love this little guy?
Oblivia: I love this region, one of my favourites. The landscape varies from island to island, so it never gets repetitive.
Signs: One of the main new features of this game, I love the idea of being able to call Pokemon when you feel like it.
Murph: Murph has been one of my favourite characters since the first ranger game, I'm glad he got a main role in this one.

Negatives (well, only one)
Ben: Ben is the partner character when you play as a girl. He's just so irritating. In the other 2 games, most partner characters would at least try to help. But he just stays on the sidelines and screams "Look out, *insert character name here*!" Really got in on my nerves.

So what are your thoughts on this game? No spoilers please, I haven't completed it yet.