I've used both. Adobe bought macromedia, so the newer versions are from Adobe. (You could say Adobe Flash 3 = Macromedia flash 10). Adobe is better then the older versions. It has more filters, better actionscript etc.
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2005 * December 12, 2005: Acquired its main rival Macromedia in a stock swap valued at about $3.4 billion adding: Adobe ColdFusion, Adobe Contribute,Adobe Captivate , Adobe Director, Adobe Dreamweaver, Adobe Fireworks, Adobe Flash, Macromedia FlashPaper, Adobe Flex, Macromedia FreeHand, Macromedia HomeSite, Macromedia JRun, and Macromedia Authorware to Adobe's production line.
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* Macromedia Flash 2 (1997) Features: Support of stereo sound, enhanced bitmap integration, buttons, the Library, and the capability to tween color changes.
* Macromedia Flash 3 (1998) Features: Brought improvements to animation, playback, and publishing, as well as the introduction of simple script commands for interactivity. As of 1998, Macromedia has shipped 100,000 Flash products.
* Macromedia Flash 4 (1999) Features: Achieved 100 million installations of the Flash Player, thanks in part to its inclusion with Microsoft Internet Explorer 5. Flash 4 saw the introduction of streaming MP3s and the Motion Tween. Initially, the Flash Player plug-in was not bundled with popular web browsers and users had to visit Macromedia website to download it; As of 2000, however, the Flash Player was already being distributed with all AOL, Netscape and Internet Explorer browsers. Two years later it shipped with all releases of Windows XP. The install-base of the Flash Player reached 92 percent of all Internet users.
* Macromedia Flash 5 (2001) Features: Flash 5 was a major leap forward in capability, with the evolution of Flash's scripting capabilities as released as ActionScript. Flash 5 also saw the ability to customize the authoring environment's interface.
* Macromedia Generator was the first initiative from Macromedia to separate design from content in Flash files. Generator 2.0 was released in April 2001 and featured real-time server-side generation of Flash content in its Enterprise Edition. Generator was discontinued in 2002 in favor of new technologies such as Flash Remoting, which allows for seamless transmission of data between the server and the client, and ColdFusion Server.
* In October 2000, usability guru Jakob Nielsen wrote a polemic article regarding usability of Flash content entitled "Flash 99% Bad". (Macromedia later hired Nielsen to help them improve Flash usability.)
* In September 2001, a survey made for Macromedia by Media Metrix showed that out of the 10 biggest websites in the United States, seven were making use of Flash content.[citation needed]
* Macromedia Flash MX was released on March 15, 2002, with the new Macromedia Flash Player 6 with support for video, application components, shared libraries, and accessibility.
* Macromedia Flash Communication Server MX, also released in 2002, allowed video to be streamed to Flash Player 6 (otherwise the video could be embedded into the Flash movie).
* Macromedia Flash MX 2004 was released in September 2003, with features such as faster runtime performance up to eight times with the enhanced compiler and the new Macromedia Flash Player 7, ability to create charts, graphs and additional text effects with the new support for extensions (sold separately), high fidelity import of PDF and Adobe Illustrator 10 files, mobile and device development and a forms-based development environment. ActionScript 2.0 was also introduced, giving developers a formal Object-Oriented approach to ActionScript. V2 Components replaced Flash MX's components, being rewritten from the ground up to take advantage of ActionScript 2.0 and Object-Oriented principles. Flash MX 2004 was the first release of Flash to be segmented into "Basic" and "Professional" versions. The Basic version was targeted at traditional Flash animators while the Professional version brought more advanced capabilities that developers would use, for example the data components.
* In 2004, the "Flash Platform" was introduced. This expanded Flash to more than the Flash authoring tool. Flex 1.0 and Breeze 1.0 were released, both of which utilized the Flash Player as a delivery method but relied on tools other than the Flash authoring program to create Flash applications and presentations. Flash Lite 1.1 was also released, enabling mobile phones to play Flash content.
* Macromedia Flash 8 (2005) is touted by Macromedia as the most significant upgrade to Flash since Flash 5. New features included filter effects and blending modes, bitmap caching, a new video codec called On2 VP6, an enhanced type rendering engine called FlashType, an emulator for mobile devices, and several enhancements to the ActionScript 2.0 spec, such as the BitmapData class, several geometric classes, and the ConvolutionFilter and DisplacmentMapFilter classes.
* Macromedia Flash Lite 2 was also released in 2005, which brought its capabilities in line with Flash Player 7.
* On December 3, 2005, Adobe Systems acquired Macromedia and its product portfolio (including Flash).[4]
* Adobe Flash Player 9 was released for Windows and Mac OS in 2006, which marked the first time a Flash Player major release occurred without a simultaneous Flash authoring program major release. Flex 2.0 was released in conjunction with Flash Player 9, and the player was continued when Flash Authoring 9 was released in 2007. For the first time in the history of Flash, the Flash Player had an opportunity to become widely installed before the release of the equivalent Flash program.
* Adobe Flash Player 9 was released for Linux in January 2007.[5]
* Adobe Flash 9 Public Alpha was released in 2006, and was a preview of ActionScript 3.0.
* Adobe Flash CS3 in 2007, originated from Flash 9 Public Alpha with several updates for integrating into other Adobe products, is released as a bundled software of the Adobe Creative Suite 3. This currently-newest version also brings ActionScript 3.0 and a new XML engine to the Flash authoring tool. It also has an improved and optimized GUI like the rest of the CS3 suite.
* Adobe Flash Player 10 beta was released on 15th May 2008 and notably introduces support for hardware GPU accelerated features like 3D graphics and programmable pixel shaders.[6]