For me that same iprober-520. The HP-547 is besides rare also AC only.
I have a Tek 576 curve tracer and I now use that a lot. At first I wanted one because it was a cool piece of test gear but the more you learn to use it, the more you do with it. I use it for transistors and fets but also to test MOV's, leakage, test relais, measure the Ri of a battery, use it as a load, charge batteries, signature analyse etc
HV diff-probe, i now use it more as the normal probes
And to my surprise a Siglent SHS-1062 scope-meter. Not only for the isolated inputs and it being portable but it has logging capability on the screen and the one thing I now use often is the scope logging. Something I did not even bother to test at first. In that mode it is a logging Vac+dc meter that can sample at very high speed but plot slow. That turned out to be a very handy function. It "slowly" builds the trace but I found out it does not miss short events. I think it just samples continue and fills its memory before plotting the next point of the trace based on the peak or average for that time periode. Handy for fast, short signals that come by only now and then. (slow like in once in every 10 seconds or so, not hours)
I use some gear I designed and build myself, most used is a IC tester:
http://www.pa4tim.nl/?p=5780And a n Inductor Saturation tester :
http://www.pa4tim.nl/?p=1859And not really for measuring but handy for repair, a transformer winder:
http://www.pa4tim.nl/?p=5731http://www.pa4tim.nl/?p=5339 for those who do not want to spend 800 euro for de iprober. This is a bit like the HP547.