I use Manual mode descents when I need high altitude shots of large landscapes in Another country. I use the SH momentary switch on my 14SG radio for Manual on/off. I flick into MM until descent rate hits 8 to 10 m/sec, then release into ATTI or GPS until FC stabilizes to about 2 m/sec, then rinse and repeat. Fun stuff, big pucker factor. Fun watching in goggles the moderate tumbling in MM, then gradual FC recovery. Never had VRS in MM descent, but also never try it below 100 meters AGL. Been up a mile more than once, and lived to tell about it. Did I mention not in the US and not in busy air space?
Kelly