Pros
The people there are great. Everyone I met was very personable and very fun to talk to and work with.
Office events are actually fun and not a chore.
No pressure, and overall a very relaxed environment. You can get your work done on your time (for the most part), and the work-live balance is great.
I've heard that the pay for full-time SWEs is below average, but IMO that's an exaggeration. The pay for interns is very good. I've found that many SWE internships in Kansas only pay ~$15 an hour, but Alarm.com paid more than double of that. They also paid all-expense for me to fly out to their HQ in D.C. twice.
Kontras
The codebase is pretty confusing at times, and there aren't many clear places to wrap your full head around it. That might've just been because I was an intern and didn't go through the "full" training, but I digress.
They began implementing an "AI-first" approach during my time there, which did worry me a bit. However, they're not a company I'd expect to make mass layoffs (nor have they ever had mass-layoffs before for SWEs).