Never.

However look to enhance any customer reviews that embrace such differences. Revolve your campaign around 1 or 2 particular reviews or customer reflections.
Read about blue ocean, ignore your competition (they will confuse you and kill your focus - do you think they are studying you? hell no!) Don't give them that validation.

My name is Humberto Valle, an actual commercial strategist and consultant with clients and projects around the world. I am also one of Arizona's best marketing strategists. That's where I reside. Feel free to google me, if there is anything I can help you with let me know ;)

Although I am wholly against keeping up with the “Business Joneses,” in terms of business development, branding, product, placement, pricing, etc., the approach you mentioned is useful if you’re commenting in a neutral space among your "peer competitors." It is also useful if, in some way, your competitor provides complementary services. The latter may lead to a referral arrangement or even a partnership. The only other place your communications strategy is useful is as an offline case study.

Platforms like Clarity, LinkedIn and Twitter are examples of where you can and should “give credit where credit is due” while demonstrating how you are different (define your Unique Selling Proposition). Otherwise, I wouldn't advise using your BRANDED BLOG to compliment a competitor (highlighting their strengths or competitive advantage) in hopes of winning or retaining customers. That will backfire. Essentially you're admitting that you're not as qualified, which you admitted to when you posed the question. It will be especially damaging if what your competitor does better meets or exceeds industry standards.

In short, unless you are without an ulterior motive, which Nick addresses in his response, don’t spend time promoting your competitors for free. People remember and keep up with shortcomings much more than they keep up with strengths. Use your time, which equals money, to accentuate YOUR positive!

I've been blogging before it was called blogging and before inbound marketing was a formal tactic. My published work dates back to 2004. In 2012, I switched from formal journalism to microblogging with significant success realized via Twitter and LinkedIn. As someone who has managed public and media relations for entities in entertainment, business and even education, I employ a comprehensive approach to marketing and communications planning.

Most salespeople have been correctly taught never to speak ill of their competition. Doing so will only make the salesperson look bad. Unfortunately, most salespeople have been taught not to say anything good about their competition, either. The reason is that by complimenting my competitors, I am building myself in the mind of my prospect.
You can read more here: https://www.bizjournals.com/bizjournals/how-to/marketing/2015/07/why-you-should-compliment-your-competitors.html
Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath