It can be very profitable if you know how to do it. Some common ways of promotion on other payperinstall programs will get your account disabled on Zango, make sure you follow the rules and talk with your account manager. Also search the forums and read what is posted to understand how Zango works, and how spyware or not-spyware they are and then make a decision.
I was using zango for a while on one of my sites. I started to get worried once I saw google was banning sites or putting up a warning page(beware, the following site is known to contain spyware) before a visitor was redirected to your site. This worried me so I took down the zango ads, for me it wasn't worth the risk of getting my domain tagged as hosting spyware by google.
zangocash is junk, most users don't install them, really the only way ppl make money from these type of sites is illegally... which is installing the software/activex componets onto users of their botnet, uninstall it, then do it again over and over so answer is no