Over priced and somewhat buggy. On my PC it seems to work fine with a few exceptions. First, the kill switch feature only works when the VPN inadvertently loses the connection from the server. Unlike other VPNs that disable the internet anytime the VPN is not connected. I think this is a security issue. Second, on the interface, it shows the previous two server locations you have used. Clicking on either one is supposed to switch you to the server you clicked. It doesn't. The VPN just disconnects and doesn't reconnect to the changed server. You have to click connect again. Third, the speed test "feature" simply doesn't work. Every time I have tried to use it to find the fastest server, the same thing happens. The test starts, measures three or four sites, then locks up. The app needs to be killed in the task manager and restarted in order to regain control. It was reported SIX updates back, but they have yet to address it, Speeds are okay. Connection stability is average. They claim to unlock Netflix if you're trying to watch the USA version from another country. Nope. All are blocked.
Now the real annoyance... My MacBook Pro. OpenVPN won't even connect. The app says it can't find an internet connection, but other apps can, When you set the protocol to automatic, there are constant disconnects. So bad that I've ditched using ExpressVPN on my Mac and I'm using a different provider. Zero problems since I switched. Yes, I have reported these problems to the support department. They claim to be working on a solution, but haven't contacted me in 3 months. They need to just rewrite the app for the Mac. Big Sur brought even more changes and the current app has even more issues with Big Sur.
Their new lightway protocol isn't very efficient for throughput. I get better speeds with OpenVPN UDP. The lightway protocol connects very fast, but is unable to maintain a stable connection so there are constant interruptions. Also Lightway is closed source. Meaning security firms can't audit the code to determine it's safety and encryption efficiency. For now, you might not want to trust this new protocol.
Conclusion... If you have a Mac, look elsewhere. The headaches aren't worth the premium price. If you have a PC, it works okay, but like the Mac, you would think these issues would be addressed immediately for a product that has such a premium price tag.
You can find better VPN services for a lower price. The premium pricetag by no means gives you better customer service. I found the CS reps to be quite arrogant and unwilling to look into problems. They offer you "canned" responses that often do nothing to address your problem. I didn't have many problems with my PC, only my Mac, and it seemed like the CS reps were completely dumbfounded when dealing with Mac problems.
I tried ExpressVPN for almost a year. It seemed to be okay on my PC but is a complete disaster on my Mac.