Hey
@swinco - Welcome to Computer Forums! 👋
I would say that they are pretty reliable, but if you are looking for absolute assurance that it will work 100% of the time a proper security system might be better.
I don’t have the Ring alarm but I have used their doorbells for a while and they definately miss the odd event, and every now and again the wifi fails despite me having a booster virtually next to my front door. For a bit of extra peace of mind and seeing who rings the bell it works great, but if I had higher security concerns I’d seriously consider going for a wired system - wired will always be much more reliable than anything that works over wifi.
More than once also Ring’s systems have gone down leaving me without a functioning doorbell so I would be a bit hesitant on an alarm system personally.