Best review sites for SaaS vendor

[P.Myers]

My client is a SaaS developer and I would like to begin some review acquisition activity.

Just wondering if there is any knowledge out there with regards to what review sites google scrapes or uses as an indicator for such products (Yelp and Yellow pages not too helpful in this scenario).

I have narrowed down Capterra, G2 Crowd and GetApp as having a good following - but any insights would be much appreciated.