I have had no problems with Zedge.
I just installed Scanner Radio and did not notice any 'extra' battery drain. I'm also used to streaming music 8 hours a day though and have a RAZR MAXX HD as well as unlimited data, so I don't care much about those things!
As for programs to stay away from:
Hidden Eye Plus was a waste of money. I tried the free version and it seemed to work pretty well so I bought the paid version which added features that I wanted. The paid program did not work at all. The Devs answered a couple emails trying to help but when those things did not work they stopped answering my emails and the program still does not work on my phone.
Last week I installed Go SMS Pro and it seemed to work pretty well but then about a half hour later after not using the program at all I pulled my phone out of my pocket and it was wicked HOT! Since the only thing I had done was install Go SMS and try it out, I uninstalled and the phone cooled down. I'm not sure what the problem was, but I didn't like the program enough over the stock Texting program to try to figure it out!
I also had dowloaded and ran for way too long a couple anti-virus apps. They work well but they are totally unnecessary as long as you get all your apps from Google Play, which I do.