experience with wix as a designer
Disclaimer: This is my personal experience and opinion only.
WIX: FOR SMALL BUSINESSES
 Wix has been very helpful for small businesses projects: There are not a lot of particular thing in mind that I expect Wix to do. I just need a platform for my store and my products, and an easy online payment yer secure, Wix does all of that great. However, I had more customers order from me with Ebay, and not Wix. They're quite a new platform.
I am still working on a small business project for a client. It has more personal information. Everything so far has been good. But I will definitely update more of a cons/pros for small businesses.
Overall rating: 8/10
WIX: FOR PROFESSIONAL PORTFOLIO
The next project on Wix was trying creating my portfolio. I started off with Wix because I had some experiences with it, or I thought I did so.
I spent hours and hours trying to figure our how to move everything accordingly. Since every pixel and alignment of objects matter, Wix has tried me crazy over little details that needs too much of my attention. 
In conclusion, Wix wasn't a good site for professional portfolio. They have everything but not the very fine thing a designer needs for his/her portfolio website. If you are a true and very detailed, organized designer, Wix isn't for you. That's why I switched to Adobe Portfolio. I've seen people using Squarespace as well.
Overall rating: 6/10
WIX: FOR SMALL PROFIT ORGANIZATIONS
After taking my time learning about the platform, I contacted a small non-profit and asked them if I could volunteer as their web designer. They definitely need some help on their website.
It took me 2 weeks to research the organization and what they do. Their website doesn't contain much information is repeating information all over and over again.
The amount of work I spent on the platform was little compare to the researches and the design process. And Wix isn't as complicated as Wordpress where people don't really clean up all the messed up plug-in. So that's definitely a plus.
Overall rating: 9/10
WIX: FOR LARGE NONPROFIT ORGANIZATIONS
I have not seen a large and long-time established non-profit organization using Wix. Perhaps it's still a new idea for them. I've seen these organizations using Wordpress tho. And it's quite difficult as Wordpress "engineers" do try to add some coding into their website. Hence make it hard for people who don't know any bit of coding language to interpret.