Easier to completely strip and easier to get a superior trigger pull. As others have noted, safety is a non-issue with these with a titanium firing pin and heavier firing pin spring.
I don't think so, I think the Series 80's are easier than the 70's because the FP block will let you keep the FP captive while you dis-assemble it, and allows the removal of the FP retainer without pressure on it, and without the chance of (boing) shooting your FP across the room. I assume you know the dis-assemble sequence of a Series 80 so will not detail it here.
I grew up shooting my dads Series 70 (but not cleaning it!), and grew up only ever dis-assembling my Series 80 after I bought it, and the few 70's I have done were different enough for me to give the nod for easy to the 80's. (since we're talking plungers/FP's only now, and not those confounded actuator levers in the frame, lol)