@mirdragon 

I've been using ER605 for more than 1 year.

1. ER605 supports IPv6, but you need to make sure your ISP provide IPv6 service;

2. If you want to manage the router with phone, it will be better to add an Omada Controller. The Windows version software controller is free to download and use, but it requires you have a PC always running. So my suggestion is OC200 hardware controller;

3. ER605 can handle more than 900Mbps however if you enable Access Control or some advanced settings, the speed will drop down;

4. Not sure if I understand your question. Local devices are still available in local network when the WAN is down. But it's the basic function of a router, I think all the routers can do it.

For me the ER605 is mainly for VPN server function and multi-nets VLANs. I'm not sure if it is good for you since you already have Deco X50. I tried to search online and I think Deco X50 is pretty good. ER605 is just a cheap router with some functions that home router won't have

  @Somnus Thanks for the reply

1) - Yes my ISP supports IPv6 and been using for the past 3 years

2) - I have a PC on 24/7 so that doesn't bother me, but what other benefits would the OC200 controller have over the PC version

3) - If I have my Deco X50 setup as AP then these should do the access control for wifi devices

4) - Currently with the Deco X50 system, if you lose the WAN side, you lose connection to all local devices due to how TP-Link have set this up. They've made all ports auto-wan, preventing access to local network devices.

The Deco X50 is good, but there are a lot of bugs in it that are preventing it from being a reliable router and would be to reconfigure them as access points.

I have used Opnsense as a router/firewall but that has issues with loosing ipv6 routing, especially if your internet goes down, which is reason was looking at the TL-ER605 especially as the price is below £50

Also which version of the device are you using V1, V1.6, V2 or V2.6 and does it matter which version you have

  @mirdragon 

I have one V1.6 and one V2.6

I asked tplink what does the ".6" mean and they said it's just the manufactory factory code.

V1/V1.6 are the same thing.

V2 adds USB Modem support. I think that is the only difference.

  @Somnus cheers as I've seen in past with TP-Link products they will update the hardware revision for products and usually the v1 stops getting the updates while other models continue to get the updates and you can't put an update for a newer revision on an older model.

  @mirdragon For your controller question: The only drawback of the software is the need for having a 247 running PC, but it's free. Feature-wise, they are the same.

If you turn off the PC or close the software, your network will operate, you just lose reports for that off period, fast roaming feature, and Captive portal until the software starts again.

  @RamtinR thanks

Still debating as managed to re-setup my old OpnSense unit, but may get one as a backup to it

we have approx 50 network devices according to the deco app which doesn't include all the smart lights