The most hated thing is keypad. Its stupid - It will not suit any of the customer - either rough users ot otherwise.
The keypad is very difficult and is not smooth as in other models. Sometimes you may endup deleting your buddys message if you are not careful. It happened to me :(
The new 4 way scroll key makes more trouble and irritating than assisting. Only use is in multi-screen SMS.
While samsung in the same price band offers colour display, more memory for SMS and address, GPRS, support for camera, Nokia 2300 is no way near its counterpart.
And the other disadvantage is, sometimes the software resets automatically - Earlier I thought of SIM problem - But lot other users face the same problem. There is some problem in the software.
Signal quality is as usual - nokia quality - Good.
And other positive points are FM radio, SMS filter - Im not very much interested in these points.
Polyphonic ring tone is good.