[showme]

I'm a novice Mac user but stumbled upon OmniWeb on the TUAW site and downloaded the 5.5 beta.
I've really enjoyed using the app and would like to purchase BUT I have a few questions (remember, I'm a novice).
1) Will I need to uninstall this beta before paying, downloading, and installing 5.0?
2) What is going to be different regressing to 5.0?
3) Will the 5.5 be an update I will need to pay for when it's released?
4) What is the best method, downloading the app on Omni's site or purchasing the software in box?

Thanks in advance for your assistance/advice and feel free to fill in with any other information you think might benefit me.