The template
Subject: A {competitor} alternative for {audience}
Hi {first name},
I read your roundup of {competitor} alternatives. The point about {pain point they mention} is the main reason people switch, in our experience too.
{product} is built around that: {how you solve it, in one sentence}. It's {pricing fact} and {one differentiator}.
If you update the post, would it be worth a look? Happy to answer any questions for the write-up.
Thanks,
{your first name}