Well, I have just taken the test ride at a suzuki show room. I must say that it is exceptionally smooth ride. Power is good, like with pillion riding, I reached 60 effortlessly, and except the fact that the person sitting behind me was imbalanced, I didn't feel any extra weight. As of now I have ridden GR 150, CB 150, YBR, GS 150. Based on my preferences I rate GR at 1 (rear brake is not all that good, but it is new may be need to set in), YBR 2, CB 150 at 3. Reason for CB 150 at 3 is that its not that comfortable, it feels like bike is putting in something extra effort during acceleration, brakes (including disk) is not as good as other two.
Next is Derbi, but I doubt that anyone is offering a test drive. Just to sum up, don't believe what others say. see the bike, ride it and then decide it yourself. Test ride is available for everyone so open invitation to make up your own mind.