2 Megapixel camera as claimed in Z710i and W710i is not true. The screen size is really small. Overall if you are a nokia user the software is fast and good but you will not be satisfied as feels like a kido phone.
Softwares packed are good and very interactive. Sound quality is also amazing. Only thing lacking in this phone is camera clarity.
Also the outside screen is not very clear and reminds you of intial phone displays likes of nokia 3310.
I will not advice any nokia user to go for this phone. Product as a whole is good but not as satisfying as any of nokia phones.
The same is the case with W710 I . There is no extra feature which differentiates W710i from that of K710i except the screensaver, outside cover and mega bass. But the price difference is huge between these two phones. But one pros is that the phone does not hang like any of nokia phones and the processing of the applications is pretty fast.