Security root topic

hi !

i have a very important question about root methods :

All these recents chinese and "exotics" methods are SAFE themselves ???!!! ( vroot ,iroot .... ) ...and the last one with KINGROOT . Which are "good" ?

these apps are backdors ? they are viruses or malwares themselves ? (trojan , IMEI and datas piracy ..... )

I see lots of discusions and rumors about these apps but never REAL devellopers opinions and tests here on XDA ( for members sensitization ) ,and i think that it's necessary to clarify ,it's important !

thank ...