A phone is what it is, what it does.
I recently upgraded to one of these after my venerable 8310 started to get a little flaky.
I'm really pleased with it. I make some calls, send some text messages and with a bit of care, get two weeks of battery life.
If you ignored the fact that the up button on my 8310 had stopped working completely then it did everything I wanted - but it was slow. Loading the inbox when you had more than 10 text messages took forever. By contrast the 6303 zips around quite happily.
In summary: it's a very good phone.