Sorairo Days didn't appeal to me so much, although the bossa nova version was slightly better. The whole 'rock chick' thing seemed to take some of the charm and fun away from her. She could give a good performance of it though.
Happy now she is back to something more pop, the video is better too showing some of the humour you expect from her. Brilliant Dream I think is still the best song and video [showing her in different costumes, and very engaging and amiable]. I really need a translation of the 'making of' Brilliant Dream video. That song and also Strawberry Melody [the 80s idol theme maybe could have been continued longer] are perhaps better than 1/2, but it has that youthful exuberance that seems right for her.
I'd like to see her release a ballad, she can sing slow songs well too. There is sensitive side to her voice and you can hear that in some of her Matsuda Seiko song performances for instance.