If you buy semi-auto, go for gas operated. Inertia is just not reliable enough for different shooting positions etc.

I carried both SPAS-12 and SPAS-15 on duty years ago. I do not think there is something really strange operating things with those. They were very reliable and super easy to shoot fast.
SPAS-15 we did not do anything else with but dragged and shot. They were like AK´s, except many of them shot more accurately with slugs than typical AK with ball ammo
Early SPAS-12 we needed to change some part (buffer or something like that) after 5-6000 rounds but never ones went at least 20k without any problems .
I do not like folding stocks, however. Our guns had detachable wooden stock or telestocks, I always carried with detachable stock either attached or removed.