If you haven't used the 7 day Boost Trial before, then why don't you try it out and let your eyes judge for themselves.
To use the Boost Pass with regards to picture & sound performance, NowTV recommends a internet speed of around 12Mbps or higher.
Personally for me the Boost Pass is more noticeable on a larger TV or Projector screen with regards to picture quality.
The biggest difference for me is 50fps for Sports (whenever it every comes back) 5.1 surround sound and the additional extra simultaneous stream is useful if you have a necessity for three streams of nowtv content at the same time.
If you are going to take a Boost Free 7 day Trial, make sure you cancel it fully if you don't want to continue with the Boost service and don't cancel it in the last 24hrs where the cancel button might be suspended on your account whilst nowtv are in the process of automatically taken the first payment.