It's been interesting to see the redesign get some industry news coverage!

Web Design Ledger:

... CodePen’s entire experience has been improved. You can still search by tags but also by collections and recent posts.

A gripe I had with the old design was how each preview loaded very slow. On a page with 8-10 different pens you’d sometimes have to wait 5+ seconds for everything to finish rendering. But now it seems like rendering is handled much quicker with no discernible lag time.

Creative Bloq:

Code-sharing community site gets overhauled with a slew of new features and UI improvements.

Developer Drive:

... one sees a plethora of new features, everything from exploring new areas to better app settings.

Martin Wolf:

If you are a CodePen user, this is a great read.

The general feedback has been overwhelmingly positive.