I've really enjoyed watching Ryoutarou, Ryuutaros, Jan and Gou the most of all, for different reasons. Ryou has a certain good hearted natured about that's just hard not to like, Ryuutaros I like because of the way he act, it's so childlike but at the same time he's got his own unique style. I like Jan because he somewhat reminds me of Ryouga in that he's the "screamy red" type, but done right, which seems to be lost on people. Finally, I'm really enjoying Gou mainly because he's got a very interesting story going on.
And I guess Deneb too, mainly because he reminds me of Ryoutarou a bit and I'm really a sucker for that character type.