Don't know if this helps but I use exclusively SSD. 4 in each PC.
Run corona all day, every day. Until recently* never had an issue but would still definitely recommend it.
I can't say I can estimate any potential speed-ups, but that's just because I've probably had this current set-up for 4+ years. and haven't worked in Corona any other way.
* Twice now I've had my c:/ drive ssd corrupt in some capacity (either dying while still under warranty or from possible faulty wires)... both times it took a long time to determine why exactly my PC was suddenly shutting off without any warning, but obviously I didn't lose any work, but did have to do a painful re-install of windows + all applications.