The only other commercial MFA software I’ve tried is Okta ASA. After fiddling with it for six months, I never did get it to work right. There were also some worrisome features. Duo I had up and running in a couple of hours abd,so far, have not found any way around it.
Also there was a matter of cost. ASA is licensed per server and every server needs a license. Duo is licensed per user. I have 200 servers but only about eight admins and developers needing access. I am still running on the free tier though I am sure the PTBs will release a few bucks to get real licenses. Any day now.
If you know how to secure an ssh server and have client software that can use multiplexed connections it really beats ASA black-and-blue.
Bear in mind I am doing this on Linux (CentOS7 and OL8) so your mileage may vary.