Should you call them "reviews" or "testimonials" on your landing page?
I personally prefer calling them "reviews" rather than "testimonials".
Why?
The word "review" tends to be interpreted as being more objective - ie. reviews are *objective assessments* of your product, in which the providers of the review have the space to give both positive and not so positive perspectives.
On the other hand, the word "testimonial" gives much less of a sense that it is an objective evaluation, and that it is more of a commendation.
In other words, a testimonial self-edits out any negative aspects of the experience, however small.
In marketing, sales and persuasion, every single word shapes the frame of how you're perceived by prospects.
And the frame determines whether someone ultimately decides to buy or renew.
For many businesses, calling your testimonials "reviews" might be a more powerful way of using social proof.