Lorand, how is your experience so far with moving from 87U to 88U?
I have the same router that you had (RT-AC87U and need a little more lenght on the signals as well. The house is on 3floors at about 500m2 and the router sits in the middle. Are on Merlins 384.5.
Was thinking about moving to the 88U or perhaps the 86U. Or connect 2 of them in a mesh perhaps, but then I cant use Merlin and thats a bit sad, so a solution with only one router would have been super.
My problem was that my kitchen was a deadspot,
I have tried a lots of solutions like moving my router, powerline, replacing my AC87U with the AC88U, but none of them worked.
The AC88U outperforms the AC87U on 5Ghz and it works as a charm even has some nice features in addition, but I would lie if I said that I have noticed an increase in distance. Tried to lots of settings, installed Merlin as well, no success.
Finally bought an Asus Lyra Mini hoping that I can connect it to a mesh network with my AC88U. The problem was, that Lyra was not compatible with the same mesh system that the AC88U uses. I could only use it by setting into AP mode (also disabled the 2.4 Ghz channel on my AC88U), connecting the first Lyra node to the router via cable, placed second one between the kitchen and the first node; finally the 3rd one in the kitchen.
This gave me a ~20Mbps in the kitchen (I have Gbit internet).
I am partially satisfied with this solution. The Lyra is not the most stable device, sometimes it goes red randomly (has to be rebooted by power cycling), was way harder to set it up than in the advertisement and on "how to videos", the lyra app looks good but is terrible and limited. The one thing it does very well is handling the clients. Even while in an internet call on my phone, I go from the kitchen to the router room, and I can't notice my phone switching nodes.
Back to the router. As I mentioned before, I installed the Merlin on my AC88U, noticed that the CPU was working on 50% all the time. Tried rebooting a few times but I didn't give it enough attention. - I don't know for sure if this was the cause, but few months later my AC88U was no longer working on 5Ghz. I have tried going back to stock firmware and resetting multiple times, but it was the same. Everything was working perfectly, but the 5Ghz channel took 2-3 minutes to go online and gave me "incorrect password" message when trying to connect to it, when I removed the password it said "Unable to connect". Currently I have sent it back in warranty and I hoping I will get a replacement.
Be careful if you go for AiMesh, the 87U is not supported.
https://www.asus.com/AiMesh/
UPDATE:
I saw today a software update on my phone that claims that Lyra is now AiMesh compatible.
I will not be able to test how they work together with my router for a while because my AC88U got defected and I sent it back for warranty. It took more than a month but finally agreed to get my money back, so instead of buying another one, I preordered the AX88U. It should take another 1-2 weeks (hopefully not more) until I get it.
https://www.asus.com/support/FAQ/1038071/
UPDATE 2:
I have spent a lot of time testing my Lyra mini with the AiMesh. What can I say. It is a mess. It is hard even to pair. Sometimes it pairs on the second time when on a bigger distance, sometimes even after 10 tries it doesn't connect even if it is near the router.
The Lyra clients are unstable and loose connection periodically. Sometimes it works for an hour then it goes into yellow and needs to be restarted. While I was using it as router or AP mode without the AiMesh, it was stable. After adding it to AiMesh, it is completely useless. It seems like all nodes try to connect to the main router only, and looses the ability to connect to each other. I hope future updates will solve this.
Maybe on wire it would work well but I have no possibility for it.