There are many review platforms

If you have a travel business then TripAdvisor is more suitable, retail on Amazon or eBay then these platforms make sense to collect reviews. Car garages use https://bookmygarage.com.

However for every other business then the most popular choices will be the below.

Which are better, which are more believable?

Which reviews invoke more trust? Times change, look at adverts on TV at the moment (Jan 2020). You will see lots of company telling you they are rated excellent on Trustpilot. Three years ago and it was feefo and reviews.co.uk, before that Facebook.

Watch more tv and you will see Google My business making inroads asking people to add reviews to support local businesses. It all depends on the brand. Google and Facebook are trusted but are they reliable. Should you rely more on specialist review sites like Trustpilot and reviews.co.uk.

We have our own opinions and the advantages of at least being able to make an educated guess on where reviews are going in the future. However, the real answer is the preference is the consumers choice. Older people may favour Google and Facebook, younger people review sites.

The solution is to drip feed reviews across review platforms. 

USA Yelp BBB (Better Business Bureau)