Should I get the blackberry 8820 or 8300/8310 ?

[m a a a r i e l]

What's the difference between the 8300 and 8310? I know the blackberry 8820 has wi-fi and costs $199.99 for a new unlocked phone. The 8300 cost $169.99 and the 8310 cost $189.99. Which one should I get and why?

Thanks