I don't.  The only Strymon Reverb I’ve ever had was the Flint, and I never found the spring in it to be all that awesome. 
The Fractal reverbs just slay.  The only thing I’d be looking for had I chosen to go big sky MX would be more direct control via knobs and convolution (of a spring reverb tank). As 
@Elric will always remind anyone “if you’re thinking of shelling out more than $500 on a reverb box, you really might as well just buy an FM3”