Everyone has their own requirements as far as security systems go both with how much they’re willing to spend and with what specific features they need.
For me, professionally monitored fire safety is a big deal, because I’m quadriparetic and I would need assistance in a fire emergency.
So I’m not interested in a system that doesn’t have professional monitoring or that only has professional monitoring for “intrusion alerts” ( contact and motion sensor alerts To the professional monitoring center, but not smoke or CO2)
It’s important to note that a lot of the low-end systems (including the smartthings models that use scout alarm rather than ADT) Can only alert for intrusions. Not fire.
I can’t say what would be the best solution for anyone else. For myself, if I just wanted a really simple “intrusion alert“ system, I would probably wait a couple of months and see what the new ring alert ends up looking like. It’s hard to tell right now because since they first announced it the whole company was bought by Amazon, so there may be a lot of changes when it actually comes to market. But as it was first Announced, it looks like a really good simple intrusion monitoring system, and it even has professional monitoring. But not fire monitoring. 
https://ring.com/alarm
But I definitely want fire monitoring. If I was only looking at systems which are available for installation today, I would look at abode (which is always very highly rated) and at the SmartThings/ADT security panel, which is very new, so doesn’t have as many reviews, but looks like a decent system. The SmartThings system has more options on the home automation side and the abode system has more fully integrated camera options. So I’m not sure which one I would end up picking, but those are the two I’d be looking at.
https://goabode.com
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If I was willing to wait a few months, again, speaking just for myself, I would wait and see how the new system from abode, the iota, looked once it was actually released. That’s because it has both HomeKit and Alexa compatibility, and that’s something that I would like. But since it’s still in pre-release, there’s no way to know what features it will actually have once it’s ready to ship.
https://iota.goabode.com
(I’ve looked at the Honeywell lyric security system with HomeKit compatibility which is available now , but it didn’t meet my own needs.)
I would also definitely schedule a free appointment with my local cable company just to find out what offerings they have for a professionally installed system. As Mark mentioned, this may cost more and you would have fewer device choices, but that’s worth it to a lot of people just not to have to deal with the headaches of installation and device selection.
So those would be my candidates. If I needed something to install today, I’d talk to my cable company, and do deep research on the current Abode system and the smartthings/ADT security panel.
If I was willing to wait a couple of months, I would wait for both the ring alert and the new abode iota to see what they offered.
But different things work for different people, so I can’t say what your best choice would be. There’s no question that selecting a security system can feel overwhelming. You have to read all the fine print in order to know exactly which features are included and it’s hard to compare systems head to head. The cable company systems will be good enough for most people, and is the easier choice If your primary concern is security. You may feel you’re paying a little too much, but on the other hand you remove a lot of the hassle and these generally have good reliability and a reasonable feature set.
If you’re trying to save every penny and get the least expensive reliable intrusion system, I would probably wait for Ring Alert.