Also memory was much better organized than Amiga - without the speed penalty.
And the simplicity of Shifter (the "GPU") allowed for really awsome 'beyond the dream' hacks, which were unavaliable on Amiga due to much more capable - but limited in 'hacking' video chip.
And then the first upgrade - Atari STE - amazes today with full control 8-channel 50kHz MODs... While mc68k CPU stayed at 8MHz!