I have seen so many clips on YouTube, sites or threads in forums where people compare Amiga to Atari ST. Then they say, look, Amiga has better graphics, Amiga has better sound. This game was better on Amiga. Those people don't seems to have understand what Atari ST was about.
From the beginning Atari ST was created to battle MAC as a "serious computer", that's why ST used a similar GUI (GEM), so similar that Apple actually sued Atari for using it. ST also used a monochrome screen for high resolution (no scanlines) and 70 Hz refresh rate that made Atari ST perfect for serious use. In fact, the screen to Atari ST was even better then the MAC screen itself. Besides that ST contained everything in ROM. Just boot the computer and everything was ready to run. Not even that, ST contained built in MIDI ports as well.
For MIDI ST was so well constructed that not even todays computers can match it for low latency times. ST was tight down to one millisecond, that's more precise then even todays computers can handle.
http://www.synthtopia.com/content/2010/03/10/atari-ste/
For gaming ST was more limited then Amiga because the lack of custom chips. While ST just used a simple frame buffer and software generated sprites Amiga contained Jay Miner's custom chips. The only area that ST could battle Amiga in gaming was in pure vector games where ST had a bit faster processor, else Amiga was (for the most) better for gaming.
But there's off course games that where better on ST, and in some cases it was simply a matter of bad ports for Amiga. But looking at many games the difference is'n that big between the two computers, it's when you use the Amiga hardware to the full that ST has a hard time to follow.
MAC was the computer for serious use while Amiga was the computer for games, graphics and demos while Atari ST was something in between, a computer that could handle both. The serious computer that could be used for playing games as well. And by some clever programming ST even manage to raise the eybrows of many Amiga owners.
So, when people just compare the computers for colour graphics and sound, or gaming, it isn't a fair comparison because ST was THE allround computer made to battle MAC from the beginning and a far better allround computer then both Amiga and MAC for it's time that could handle serious business applications on a high quality high res monitor and in the next time being used as a games machine hooked up to any TV or colour monitor.
Even Amiga was from the beginning a computer that Commodore wanted to advertise as a all-purpose business machine, but very soon Amiga became something else as we all know.
Many people who bought Atari ST was kind of surprised, including me. Atari was supposed to be about Jay Miner and gaming, but not this time. In fact Amiga was way more similar to Atari 8bit then ST ever was.
This is Atari ST when showing it's real strength. In fact, Atari managed to create a very competent allround computer. Far more allround then Amiga or MAC ever was and the high res monitor was a bless to use for serious work.

The only thing that not many Atari or Amiga fans want to hear is...
Jack Tramiel once started a company called Commodore. In the beginning it was about manufacturing typewriters and cheap office furniture. Then Commodore bought a company who manufactured computer chips.
From now on, Commodore was about making computers.
Many years later Jack Tramiel got frustrated over his partner and left Commodore. He didn't left Commodore alone, a whole bunch of people left Commodore together with Tramiel. Then Jack Tramiel bought the rival company Atari. He sacked most Atari employees and replaced them by ex Commodore people.
Shiraz Shivji, one of the designers behind C64 became the father and lead designer of Atari ST while Commodore used the service of an ex Atari employee, Jay Miner.
The result
Amiga became more similar to Atari 8bit then Atari ST ever was. Atari ST was designed and marketed by ex Commodore people.
In that case, it's lots of Atari in Amiga and lots of Commodore in Atari ST?