The cheaper ones don't have their AI smart person/vehicle detection. Trust me, you want that.

If you don't get that feature, you're going to be flooded with false alarms. So many that you're going to be frustrated by all the false alarms and you'll turn your notifications off. Again, trust me... I've been there. I used to wake up to hundreds of false alerts every night.

The only way I'd recommend the non-AI system is if you only wanted 24/7 recording and didn't care when it detects motion.

Now if you want to get the lower quality 5mp cams but still have the AI alerts, you would look at this one: https://www.amazon.com/Security-Detection-8-Channel-Recording-RLK8-510B4/dp/B08F5F69B8 and since I'm assuming you want 6 cams, you'd then buy 2 more cameras separately.

By the way, there's an official Reolink subreddit if you want to ask more questions: /r/reolinkcam