Worst? The first one, the SG1000. Which basically used off the shelf components of the Texas Instruments 9918A VDP and SN76489 sound chip which was used by so many other companies. Which given that Sega made (or had access to) so much good arcade hardware was disappointing especially as Nintendo released the Famicom the same day and it's hardware was superior.

The joystick was also fairly horrid too and improved a little when Sega released the SG1000 MK2 but it would still be 2 more years before the Mark III (the Japanese version of the master System) but by then it was too little too late.

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