Listeo has option to show 5 latest reviews from Google Reviews for the listings.
To use it, you have to provide Place ID for the listing. If you are using Google Address auto suggestion feature, this will be automatically set if you choose a business/establishment/place from the suggestion list (yes! we have now option to actually search for places, not just address).
If you are using other map providers, you can get the Place ID from Places id-finder
Places API allows to show only 5 reviews from that, those results are cached for 48 hours to not generate additional costs for API. To use that feature you need to have API key set for radius search (Listeo Core → Map Options → Google Maps API key for server side geocoding).