Depends on the circuit.
Vactrols are quick and dirty but man, dirty. Slow and imprecise. Particularly problematic if you try to drive one directly with a CV instead of an op amp driver. Non exponential unless you build an exponential converter, and then it’s not quick and dirty any more. But there are situations where they’re just the thing, when you don’t need fast response (it’s even a feature, not a bug, sometimes) or great precision.
LM13700 is very useful for this, but of course the DIP version is out of production and getting harder to find (genuine ones anyway).
For my Barton/AO 4046 VC Wave Shaper I needed 7 voltage controlled amplifiers — except the signals were pulse waves, so I could do something equivalent to a VCA using nothing but 1/4 of an analog switch and a resistor. And an op amp as it turned out, it needed buffering.
See also