Sylvia, I can't recommend other companies and haven't taken this tour but here's why I'd personally skip it? Based on a previous post, it looks like you'll be spending 4 days in Rome? This means that you'll run across many of the locations on your own so you'd be doing some backtracking, For instance, the tour goes to St Peter's Square but not INSIDE the basilica or the museums so you'd be coming back for those. Other locations - such as the piazzas and the churches - are very easy to do en route to other attractions.
For that reason, IMHO, spending 130 euro for a 1/2-day tour seems like an expensive endeavor for something easily accomplished by yourselves, without backtracking, and with the ability to spend more time at some of them than the tour is likely to allow.
Just a thought, anyway? If you do a little googling around, there are even some self-guided tours online that you could download, like these:
http://www.slideshare.net/florfsmb/a-selfguided-angels-demons-tour-of-rome-by-fsm
http://www.italylogue.com/featured-articles/a-self-guided-angels-demons-tour-of-rome.html