Constant Contact or ConvertKit? Which is better?

Hi. I am running a small business organization. I am using Constant Contact for my business purpose. I was creating campaigns using various templates before. I had a doubt that my emails are not hitting my subscriber’s inbox. Then I saw a review of Constant Contact Vs ConvertKit, claiming that text-based email will most likely end up in the inbox and not in the Spam folder. Now I am thinking of migrating to ConvertKit. It also has a free version. What do you think? Can I migrate to ConvertKit?