Don't know much about the Rigol, I tend to stay away from Chinesium ...
But,
I've got an old and crusty TDS420 (just a smaller BW model of the TDS460), and my advice would be: stay away from that beast, except you get it for free or very few $
It is known to suffer from capacitor plague, so maybe you'll have to replace a lot of small SMT electrolytic caps one day, or someone would have done that before.
It has a quite low single shot sampling rate (100Ms/s afair), for a 150MHz scope (the TDS420 model), one would expect at least 1Gs/s today. Doesn't matter too much if you want to display repetitive signals, it just slows down then.
Having 400MHz BW is nice, but IMO not necessary for what you intend to do.
Best thing would be to check them out both, to see the difference in UI concepts (I don't like the TDS420 style menus too much, I'd prefer TDS220 style - one knob per channel, not select channel and then use the same knob for each channel).
And, the TDS460 is large and heavy (though not a real boat anchor), the Rigol is small and lightweight. That's a plus for the Rigol.