I have noticed on here that some of your quotes appear in a normal vB fashion while other are more funky, like you have used <legend> for the word quote and who is being quoted and <fieldset> for the quote text.

how does one achieve this?

The alt pro style uses the <fieldset> to create the alternative quote bbcode.
If you have the pro style license, you can copy the bb_code template html and put it in your other styles on your web site if you want to use it.

This is propertie of the pro style !

The ProDefault, the ProAlternative or the PixelPro?

I have installed the ProDefault and the quotes are appearing like the did with the original vB style, only the colour has changed.

Also what bbcode controls this?

The pixelpro is a style created by danielc from infusesoft.

The vbnl pro default uses the default vbulletin 3 bb_quote html
and the vbnl pro alteranative uses the <fieldset><legend> html for the bb_quote

to change the background color in the quote from the default style , change alt1 to alt2 or alt2 to alt1.

One lat point. Do you have a rough list of differences between the default and alternate style?

Edit: Ignore this. I have sorted it out. Thankyou for your help.:)