The Remington 870 is one of the forum's favorite shotguns and is very highly regarded. See how often it's mentioned here:
http://thefiringline.com/forums/showthread.php?t=370135
The SPAS 12's with the lever style safety are defective, and can fire when the safety is activated or deactivated. Look here:
http://spas12.com/spassafety.htm
I don't know much about the Winchester 1200.