What is the biggest difference between CrowdStrike and Cylance?

Both Cylance and CrowdStrike are amongst the few top of the market in terms or endpoint protection. CrowdStrike was considered among the top 5 in 2017 and Cylance was considered the same in 2019. As they are both highly effective, CrowdStrike is very unique in its user-friendliness, while Cylance is very unique for its minimum utilization of computer's resources. If you compare initial pricing, you would go with Cylance, but you can always negotiate with both to get the best offers.

I had a great experience having deployed CrowdStrike to tens of thousands of endpoints. It's easy to deploy and operationalize. It has provided protection against threats that other engines did not catch based on its powerful heuristics and AI.
CrowdStrike does invest heavily in R&D and provides advisory services on endpoint protection.

I never used Cylance. We installed CrowdStrike on 6/6/19 and aside from a test file have had zero hits. CrowdStrike has some additional features available (at a cost). One that I am looking at is device control for USB storage devices for policy enforcement. Syslogs are being absorbed by my SIEM as well.