I love the ease of administration, rolling out new users, handing out machines, and remotely managing our workforce that is across the country. The tie in to G Suite and Office 365 make managing usernames/passwords so easy for our team. I also really like how easy it was to establish a RADIUS server using JumpCloud and Meraki AP's.
I have trouble getting the "Commands" to work consistently (think Group Policies with AD), though I suspect it is with my skill writing scripts than something fundamentally not working. I would like more access to reports to help troubleshoot. It seems you have to utilize the API, which is not overly difficult using Powershell, but I wish it were built in. I've had some false positive lockouts on users that I had a hard time troubleshooting where it was coming from.
I get why, but switching from AD, it was kind of a pain transitioning machines. New/clean machines are easy, but you have to unjoin the domain first, so this made rollout to end user machines slightly more of a headache.
Also, this is more of a complaint on Microsoft, but JumpCloud only works if you are NOT connected to a AD Domain. However, with Windows 10, Microsoft prompts users to enter their Office 365 credentials all over the place, so my users inevitably enroll into the Azure AD service bundled with Office 365. So it can break the connection to jumpcloud. That one fortunately is easy to fix.
Lower cost of ownership, and ease of use so we don't have to spend time making configuration changes. No reliance on hardware makes it easier to manage both on-site and off-site workers. Allowing users to manage a single username and password across their PC logins, G Suite, Office 365, RADIUS wifi access, and just about everything else.