I have a Heathkit SP-2717, great bit of kit but due to its age you’re going to have to go through them and replace the electrolytics, measure all the carbon comp resistors, and test all tubes. But that is all part of the fun right?
In real world use i find it invaluable, i much prefer having analog current and volt meters because you can see what is happening real time. One feature it is lacking is the ability to set a current limit which could be useful.
Note there are a few versions, IP-17,SP-27,SP-2717,IP-2717 etc. The early models used a tube rectifier and a string of gas regulator tubes for the negative supply, the later models used diodes and a string of Zeners for the negative supply. My SP-2717 is all tube based.