Product Recommendation based on purchase history
Even if you don't have ratings or reviews, you can use the customer purchases to help creating your model and selecting the most appropriate one. If the customer has bought the product, you can suppose he has liked it. If he hasn't, we can suppose he has disliked it. This is an approach which is mainly used by e-shops.

You can find more on recommendation system selection and validation below. It is discussed how to choose the best recommender with both offline and online approaches. 

https://medium.com/recombee-blog/evaluating-recommender-systems-choosing-the-best-one-for-your-business-c688ab781a35