My opinion (you asked for opinions right?) is that the rust you show isn't really anything to worry about. It seems to be mostly surface rust, which isn't unexpected on any vehicle in the areas you show. The trailing arms, suspension arms, and body all look to be sound - and those are the parts you actually worry about.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)