Opinions of Darwin/OS X (Apple Computer)

I was wondering if anyone actually had an opinion on the Unix Darwin or its GUI OS X? Is anyone using it as a development platform? I thought I would ask outside of the usual Mac discussion areas to see what was really out there.

Yes I use it all the time to develop php/mysql web sites, test out Unix scripts, crons and all sorts of other stuff, I also run Virtual PC If I need to run windows. The mac lets me develop all aspects of my web projects including graphics, multimedia etc Usually with Dreamwever/Flash and fully test them before uploading to my freeBSD based dedicated web server. I've not yet had a problem on the live web server if it worked ok on the mac. I even redirected a domain to my mac (powerbook) and hosted a clients site from there whils the live server was down for maintenance .