I recently restored a North Star Horizon and Advantage to working order.  A few of the S-100 buss cards required capacitor replacement but aside from that worked just fine.

The Horizon is connected with a Televideo 912C terminal running CP/M and Word Star.  A Diablo 630 daisy wheel printer provides high quality output.

The Advantage is running the North Star Slide Show with the Van 9 presentation from Juan Rivera.