seo Wordpress to Squarespace Migration - SEO Impact

I have a potential new client who wants a website refresh - but their current site is in Wordpress. My preference would be to migrate their site to Squarespace, and they are open to the idea. But they are concerned about losing their organic rankings.

Can anyone who done a Wordpress > Squarespace migration give me some insights into how their SEO was impacted - how much of a drop, for how long etc? 

Thank you.

Hi! I did this for a client a year or so ago. We were not hit as hard as I was expecting, we dropped 1-2 places, but recovered within the first 2 months after launching. We kept the same domain. Overall, I was glad we did it for them.