Single IP vs Multiple IPs w/jails

[Chris]

The ISP that I will be colocating with has offered an extra set of 4 IPs (for a total of 5) for a very good monthly price. I will be using jails to host 4 websites. Notwithstanding the extra (minimal) costs, 

1) what would be the advantage(s) or disadvanatage(s) of giving each website it's own IP vs sharing the single IP?

2) Is one going to be more difficult to set up than the other?

3)Would it be easier to use WebAdmin to configure this setup instead of trying to do it by hand? I think I'd rather learn to manually configure stuff, if practical.

Thanks for any advice,
Chris