What are the differences between spark plugs?

[Pheonix]

Hi All,

Am wondering if there is any point to these premium spark plugs the manufacturers keep banging on about?

For instance, one ebay seller is selling these:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... %3AIT&rd=1

But are they actually any different from these:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... %3AIT&rd=1

In terms of what they achieve...considering we arn't talking performance motoring here, only general driving of a 1.0 106

Was interested to know if their advertising rang true or not

Cheers
Joe