The TRS-80 model 1 had a lo-res display and was black and white without a sound chip. The Coco added higher res color and sound.
Commodore 64 had better video and sound hardware than Apple and the Coco, including game-oriented features like pixel-level hardware fine scrolling, sprites, and user-defined font sets to use as maps/backgrounds.
The Atari 800 had better graphics hardware though, since it used a display list and color palette.
Most people don't realize this, but the Amiga was the successor to the Atari 800, while the Atari ST was actually the successor to the Commodore 64: The Atari engineers moved to Commodore while Jack Trammeil (sp?) left Commodore and took over Atari.