Google announced on Google+ that you can now see the reviews your friends left on Google+ Local from their Google+ profile.
To do so, go to a friend's profile, click on the "about" tab and scroll down to the "Local" section. If they have reviews, it should show the number of reviews and the number should be hyperlinked to show you a landing page of all of those reviews.
Here is an example of +BradleyHorowitz:
That link takes you to this landing page showing you all the reviews he left for places on Google+ Local.
This can come in handy if you have friends who you trust about certain types of places.
Forum discussion at Google+.