the new n-series such as n76 n95 and 6110(eventhough not n-series) r using symbian V3.1 with feature pack 1 which makes the operating system more stable than the old n-series like n73 n80 etc..also the CPU Clock Rate on the n73 is 220 MHz whereas n76 and 6110 r 369mhz which makes the phone faster than n73, the n95 has cpu of 332mhz but its using dual cpu, the SDram memory on n76 6110 r both 96mb where as the n80 and n74 only have 64mb, the bigger the sdram memory the better it can handle with multitasking and result less hangs/freezes on ur phone, so if ur looking for a symbian smartphoen go for 6110/n76 or n95, i have used n70/n80/n73/n76/6110/ before, and currently using n95, my recommendation would be 6110 since its more stable and faster on series60 V3.1 platform, the speaker r loud and clear,gps works great and series60 allows u to add endless applications on ur phone, but if ur not into series60 than just go for ur w660i..all depend on ur need