I too came from SimpliSafe but I had the original v1 system. I bought the one year subscription to Wyze Home Monitoring System (WHMS), so I got the starter kit for free and added additional sensors.
(I’ve also been experimenting with an RPI-3 and Home Assistant, so I can utilize the different motion and entry sensors as well. I can even have it arm and disarm automatically as I ever and leave my home area (but there are many other factors to consider before doing something live that, and it’s not recommended for everyone). You can even integrate it into Alexa scenes when using Home Assistant… But I digress.)
So far I do love the system and I find myself using it a bit more than my old SimpliSafe system. But there have been a few caveats and considerations.
I’ve been having an issue with the battery backup not reconnecting to Wi-Fi when power is restored… but I believe it’s an individual issue in my case as most people don’t seem to have a problem.
The current WHMS only offers entry and motion sensors… But they are already planning on releasing some other sensors that would match the offerings from SimpliSafe, like water sensors and humidity sensors. There’s also been some discussions of integrating glass break detection from the Wyzecams into the home monitoring system.
The one difference to keep in mind between SimpliSafe and WHMS is that simply safe has its own cellular connection so it does not rely on phone or internet for communication. Someone could literally cut the power to your house and simply safe would still communicate with the monitoring center. In the case of WHMS it relies on Wi-Fi… So if the power goes out you have a local system only.
All in all, for the difference in price as well as the added features of integrating into Home Assistant, I can’t recommend it enough. But as a potential new customer, you’ll have to keep in mind that it’s a system that is still growing and improving, and you won’t have cellular communication.