I have a couple and the trigger is a little rough in DA but pretty decent in SA.
Yugo Zastava M70 is commonly mistaken for Czech CZ-UB Vz70
Like others have stated Yugo M70 is single action and looks sort of like a little Tokarev TT-30/33.
Eastern Euro manufacturers get confused easily, particularly after becoming only partially govenment owned. Many Eastern Euro firearms companies use the letters C. Z. in the company name, if I remember correctly C. Z. stands for what roughly translates as "Czech Weapon Factory" in english. There are many "CZ's" in Eastern Europe- CZ-UB, CZ-Arms Moravia, CZ-Strakonice, CZ-Brno.
As far as the Yugo CZ M70 if I remember correctly it stands for Crvena Zastava or something like that, I dont know what the translation means.
here's a good link explaining the differences between the various CZs
http://p201.ezboard.com/fczechpistols82792frm25.showMessage?topicID=139.topic