I like Flash. Really, I do. I love all the subtle animation and graphical effects it makes possible, and how seamlessly it can be integrated into websites.
However, when given a task I can perform using either Ajax or Flash, I always prefer Ajax. There are a number of reasons for this; let me illustrate one.
Recently, a Macromedia employee created a Flash version of Google Maps to demonstrate how much better it would be in Flash. Not a bad idea. But, when I visited the site using Firefox 1.0 on my Mac PowerBook (OS X 10.4.2), the Flash version proceeded to drive my CPU usage up to 100% and render my browser completely unusable. I had to Force Quit the sucker.
I know, I know. It’s unfair to judge the Flash movie based on this experience. After all, its just a hacked up demo. But… I’ve yet to have any Ajax demo hang my browser. Hmm…