I've done a fair bit of repair on tube radios with my local ham radio club. The older analog scopes can work well, but most are old enough to start needing repair, and many types of scope repair can require a known good scope for diagnosis. So you may have to start a collection if you go that route.
What I personally find most useful is a Rigol 1054z with at least a couple of fixed 100:1 probes. Tube radios are full of high voltage, high impedance circuits, hence the 100:1 probes to bring the voltage down and avoid loading the circuits.
The modern Rigol will do many tricks the old analog scopes wouldn't do, and it has enough bandwidth to directly see RF throughout the HF range, where the old guys would settle for using an RF probe that could merely detect the presence and magnitude of a signal, without seeing its frequency or waveform.
Having said that, the guy in our club I most respect really prefers older analog gear. He learned with it, and finds it faster and easier to work with. He detests the menus and overloaded buttons/knobs of a computerized UI. I see his point, even though I find the features of a modern scope worth the trouble of a few menus.