if texting is all you do, you'd do great with the nokia. the two main advantages of the nokia are:-
1, it's a smartphone
2, it's got a full QWERTY.
however, there are places where sony wins without a doubt.
the camera quality is by no doubts better than that of the nokia, the nokia doesn't even have autofocus.
Plus it features sony's high quality music player.
A weird thing about the nokia is the lack of an external abc keypad. the QWERTY needs to be slided out in order to dial a number for a voice call, and this is pretty odd.
if i were you, i'd stick to sony.