IIS takes a lot of configuration for a newbie whereas wamp server installs first time with everything good to go.
Other extensions in PHP can also be enabled at the click of a button rather than uncommenting lines of code in the php.ini file.
It also sets up MySQL very nicely with PHPMyAdmin for management.
Save yourself some time.
I would totally reiterate these sentiments by Geordie. It is the easiest and fastest setup and easily run programme and covers all the bases!