Google is very wary of any data or element found that can artificially influence it's results. Throughout the years, Google has made a few mistakes here and there in it's algorithms that allow people to manipulate the ranking of a site, however, that has always been within very narrow margins and not a general rule only effecting a site in small ways. The reason for this is simple. Google is made up of human capital that is often separated into stove piped efforts (groups) where communication between them has allowed a "hole" in it's algorithm. These are often found and fairly quickly fixed but not always as fast as we would like. One example was the exact match domain name. While it is still true that term matches in a domain name can positively influence how a page is found, keeping in mind that the content still must be relevant to the search query, for a while, search term matches found in domain names were over-optimized and would bring a particular site to the top of the SERP list. This is no longer true except in smaller ways and only if the search query match is a strong one.
Google has a general rule. If a site owner can do something to influence search results other than through the ordinary means of content and site creation, then Google will not put influence on the data or content element. Why? Because then anyone can artificially influence results. SEOs, for a long time, would look for these holes in the Google algorithm. By and large, these so-called holes were nothing more than a small or narrow effect. The game of manipulation has been whittled down over the years and largely a thing of the past. Google wants honest results from honest sites.
Be that as it may, reviews can be a powerful thing, however, they do not influence a sites rank or influence a SERP link placement. The exception to this rule is for Google+. Why? Because users are fully vetted and Google can rely upon the results as being genuine. Otherwise, reviews can be manipulated artificially. Reviews will sometimes be used in SERP snippets. However, Google+ reviews can move a SERP link up one or two positions assuming that the search query and results are relevant. Reviews of any kind found within a SERP snippet can influence CTR (click-through rates) and over time influence where a SERP link is placed. This along with bounce rates, time spent on page, time spent on site, and other metrics are the required metrics to make this happen. This means that while reviews have a positive effect, reviews are balanced with actual site performance metrics to ensure that a site is a relevant search query match. Both machine and human influences are used.
If the question is to use reviews, I would say Yes! If the question is to manipulate reviews, I would say do not do it. Why? Two reasons. Google can compare reviews from different places and use algorithms to know where reviews come from. This allows Google to know if a set of reviews have been cherry-picked and therefore an accurate representation. As well, please consider that algorithms can be used to recognize natural curves within a set of reviews to know if reviews are likely influenced or manipulated. Both are done with remarkable results.
Lastly, separate the use of the term "rank" into two camps. One is site rank and page rank where metrics are stored within the index. The other is SERP rank where metrics are applied dynamically during the search query process and orders the SERP list. Reviews never influence a site or page rank. However, Google+ reviews can influence if a SERP link is raised one or two positions as a result of a fully vetted and trusted set of reviews.