There are lots of XAMPP installs out there running, but bein' as this package is NOT a production platform (they say as much), it really doesn't make much sense to even start with it. WAMPServer2 seems a little more dependable as an install (of course, Moodle goes in separately), but even so, it does make sense to just get to know the pieces individually anyway.
As for IIS, we moved to IIS this year, and although, overall, it's done fairly well, there are lots of WIndows "gotchas" we've been gradually wading through. As an Internet service, Apache seems a lot more stable, dependable, and simple. We moved 'cause nobody around here seems to want to support it (we're an all-Windows house), and we were worried about PHP acceleration (we're a big install).