Well....... PWS is lighter when compared to IIS. However, in the long run it's just going to make your life more difficult. IIS is weak compared to Apache, so what does that make PWS? Do yourself a big favour and grab the latest Apache (1.3.20) binary distribution from apache.org. As of 1.3.19 Apache can be installed and run as a service on Win98. Using Apache will, among other things, allow you to develop on a production grade server (although in a very non-production grade environment).
PWS also inherits most of the issues that IIS has regarding security, stablity, and standards conformation. For example, IIS and PWS report server paths like DOCUMENT_ROOT using the Win32 backslash. Logical enough since that's what the OS uses until you consider that URL's use the *Nix forward slash which ends up creating headaches with REGEX expressions.
PWS is a very scaled down version of IIS, and should be treated as such. When at all possible you should try to mimic your deployment environment and since PWS is pretty far removed from IIS (and most hosts use Apache for their PHP-enabled servers), Apache is definitely your best bet. There are pretty good reasons why Apache has a greater marketshare than all other httpd servers combined๐ HTH.
Geoff A. Virgo