Great quality, extremely useful features, easy to use, fast response, clear UI, 4 channels! at great price due to age
HP 54-series scopes provide amazing value for the money. They are inexpensive due to the age but offer amazing features and very clear and easy to use interface.
The interface is the same among the 2 and 4 channel scopes. "Auto scale" function is pretty fast. "Hold" function allows for an off-line analysis. The CRT display is definitely superior in terms of latency - especially comparing to cheap fully digital scopes. Cursors and "meas" functions allow to measure dv, dt, frequency, duty cycle etc. This scope is designed and made in just right technology allowing for DIY fix (when bought broken). Knobs are very responsive but have just enough resistance to provide the feel of sturdiness. Boots up very quickly compared to the new cheap digital scopes.
The only downside is that it is hard to get the replacement parts for it.