Well, let's see if I can field that one.
CompTIA Learn and CompTIA Perform are very similar platforms, where you basically read the text in the form of modules, answer 'end-of-module' questions, and do some Performance-Based Questions (PBQ).
Perform is the next evolutionary step after the acquisition of TestOut's LabSim. LabSim provided module by module text but also had a much more mature and developed simulation engine than CompTIA had. Perform will integrate those virtual live-labs that were part of LabSIM with the Learn material.
Some might say that Learn is for people who really are getting their first exposures to the material whereas Perform provides that content but more of a "real-world" application of skill.
I personally have not gone through the A+ Perform material; right now, I'm doing the SecurityX Perform walkthrough, since my credential comes due this year, so I wanted a somewhat pure evaluation of the Perform product to Certification. I'll evaluate against other tools like Udemy's courses as well.
So, that's the scoop. Learn for newbies, Perform for those going further.
/r