In one sentence -- I do more in ColdFusion faster than my programming chums do with JSPs or PHP, and the code looks cleaner to boot.
As the above poster mentioned, there are oodles of features that come packed into ColdFusion. They make development faster, meaning I can spend more time fine-tuning my sites for my customers' specific needs.
Jeremy Geelan of CFDJ (
http://coldfusion.sys-con.com/) wrote a solid article outlining far more eloquently than I the solid points of using ColdFusion. Gah, I wish I had a link to the article now -- I have the actual paper magazine at work (I'll see if I can dig it up tomorrow). The jist of it was that you'll make back all the money you spent on purchasing the server by cutting your development time.
CF is a RAD tool for Java web applications. It takes the best, most used functionality you'd want from your JSP and makes it easier for you to code. If CF doesn't have a tag for what you want, you can take advantage of the Java API at will. Build custom classes, custom tags, and whatever else you need to get the job done. In my experience as a CF programmer, I've never *had* to resort to such methods. ColdFusion out of the box does practically everything I need i to. Saves me time (not to mention headaches :)), and lets me spend more time tweaking the "web experience" aspect of the site rather than gritting my teeth debugging an app.
Thinking to web 2.0. How does PHP connect to a Flash Application? Most of the examples I see from the PHP world involve creating XML files, and passing them into the Flash application. How does ColdFusion do it? I just have Flash make a call to a function in my CFC that I've already written for my non-flash version. I don't even have to deal with converting my Query object to an Array. ColdFusion does that for me. Want to use Flex 2 with ColdFusion? No problem -- Works the same way. This is THE reason I love Adobe these days -- Everything works together seamlessly. I don't need to waste time searching online for solutions because Adobe's already built them and packaged them into the API.
It's well worth shelling out some dollars to streamline your development process and build better experiences for the customer. Especially if you are thinking of leveraging Adobe's near-monopoly on visually interesting content (Flash & Flex).