Tl;dr - this product is AMAZING and the best technology product I have purchased in a year. It does something that is important to me that I've struggled to find an effective solution for years.Pros:- Sufficiently powerful- Does not create a performance impact if properly configured- Easy to monitor remotely- Works across multiple devices- Provides both insight on technology use and control- Allows you to set service level restrictions (e.g. limit Fortnite to 1 hour/day)- Great price point.Cons:- It can cause your network to break in ways that are not obvious- A bit complex to set up- The service groupings (e.g. “Email” or “Online Gaming”) are not customizable- Mobile only administrationOverall a solid product and well worth the cost.Detailed Review -A bit of background - I'm technically adept and understand my way around my own network. As my kids have become teenagers, my struggle has been to effectively parent their online behavior. On the one hand, their devices and technology are an important part of their school, social lives, and even part of our family connectedness. On the other, I've been concerned about how much time my son spends on Fortnite and Youtube, and about my daughter's technology use late at night.Our solutions to this have largely been ineffective. We’ve tried having the kids leave their phones downstairs when they go to bed, but that doesn't address what they do during the day, and it has been a source of conflict. I've tried controls using my router, but they haven't been time based, nor sufficiently granular - e.g. I couldn't easily stop face time on my daughter's computer without affecting her ability to do homework. iOS 12's Screen Time feature has been helpful, but that only provides data for a single device and it is somewhat unreliable.The big problem is that we can’t easily know exactly what they are doing without policing them, let alone come up with effective constraints.I finally found a review online for the Circle. It seemed good, but I was concerned that 1) it might not work with my router (I use an ASUS AC5300), that it would create performance issues, and that it would not provide sufficient control to deal with the issues that we care about. However, I figured I would give it a try.The key to how this product works is that it uses some obscure aspects of how networks work to give the circle the ability to see the network traffic that goes into and out of your house for any device or collection of devices (the technical term here is ARP Spoofing). Without getting into the technical details, if you connect the Circle via the ethernet cable, it does not create a performance issue. Moreover, any device configured as “unmanaged” is left alone. This is something I was particularly happy about as my home network has a lot of devices on it and I like the control.Installation:Installation was a bit obtuse. Despite being connected via ethernet to my router, I still had to use the WiFi network to setup the circle. Moreover, the Circle only understands how to talk to 2.4Ghz networks. That said, once everything was done, the wireless network was not an issue.Setup:Once setup I created a test profile for myself to see how well the device worked. I was pretty amazed at how easy and powerful it is. Profiles allow you to connect multiple devices, define specific constraints on a service level (e.g. Youtube), and these constraints work across all of the devices on the profile. Moreover, everything else is left alone.Once active, I immediately got what I was looking for:- Time spent on a variety of different services (YouTube, Fortnite, Gmail)- Identification and monitoring explicit content sites- Ability to set constraints, as either hours (bedtime and blocked time)- Ability to set time limits (yeah!!!!)I found the monitoring/time calculations to be pretty accurate. The only limit is that they are limited to 5 minute granularity - which is fine for me. Once the Circle chooses to block a service, it happens pretty immediately. Some things like youtube take a bit before the block is noticeable, but everything else is immediate. Restoring service is also immediate, though there can be some problems (see issues below)What I LOVE:- This device allows for granular control over services. Meaning, you can allow for web browsing and email, while blocking video games and netflix. You can block one device but not another.- You can set up profiles for your family that work across multiple devices. No more temptation to cheat by moving consumption from one device to another- For my network, the device even worked on the guest network which means my kids couldn’t get around it that way. It did not seem to affect our AT&T Micro-cell traffic however- The device provides both monitoring and prevention. This allows me to have conversation with my kids where we now have an objective definition of time spent. Moreover, it allows them to see how much time they are spending so THEY can set the limits - Now I get to parent as a coach instead of as a policeman.- There is no noticeable impact to my network performance. I have a 400mb/s connection to the internet and have noticed no impact to my network latency or performance from the Circle.- It is pretty easy to use once it is set up.Issues:- It’s not perfect however and there are some things to be aware of:- I can’t easily customize what Circle monitors/blocks. Circle’s pre-defined categories are pretty good, but if you want to change something it is not easy - and in some cases not possible. I would prefer to have more flexibility than the device provides, but given the ease of use it provides in other ways I can live with this constraint.- Networking problems - the way the circle work can create compatibility issues with your router. Circle has put a pretty good compatibility chart on their website you can check - strongly recommended that you do this before buying this device- The Circle can cause your network to break - in my case, if I make a change on my router, it can cause my entire network to freeze until I reset things using some fairly technical commands. This may be somewhat specific to my router, but when it happens, it is not something that the layperson could easily fix. I suspect that the routers that are marked as fully compatible (mine is not) don’t have this issue, but I was unable to test this.- The Circle is hard to reboot - it has an internal battery which I suppose is nice for power outages - though seems unnecessary to me. However, when something goes wrong, you can’t power cycle it easily.- When the Circle unblocks a service, sometimes it takes a while for the service to be restored. There are multiple reasons for this. In one case, I had to reboot the router my son’s Xbox was connected to to restore service. When I tried to reproduce this it didn’t happen again, but I’m suspicious that this isn’t the only time I’ll have this problem (for those who are technical, clearing the arp cache tends to clear these issues).- When the Circle blocks a service, it routes the blocked user to a web page full of Disney content. Not the worst problem in the world, and this is the only time that “Disney” shows up in the product. I’m sure some VP is very proud of this.There is no web console. I would prefer not to manage this just from my phone.In the end, this device does way more than I had hoped - esp. For the price. It has brought me a solution to a problem I have struggled with for years. I’m a very happy user and feel that the benefits of this product fully outweigh the costs. Moreover, I like that it is something I can use to have a better dialogue with my kids about their technology use. It enables both “trust but verify” type monitoring, as well as specific and detailed constraints.Great job!