I don't really pay attention to signal strength as a 'number'. I stopped doing that many years ago. Wastes too much time for little direct benefits. As it does not (always) correlate to anything important in a customer's home (stability, throughput, or reliability); there are other (non-Wi-Fi) factors that affect those important aspects too, and signal strength doesn't factor those in.
In other words, there is no single aspect that we can measure and point to and then say, 'the network will be '
great' now'.
In my customers' homes, where I've installed the RT-AX88U and the RT-AX86U, they have both exceeded mine and my customer's expectations.
The latter replacing an ISP's router and many 'extenders' with more throughput, more reliability/stability, and a more responsive network overall (the difference was night and day actually) in their 3-story home. Here, I was expecting to exchange the router and put in the RT-AX88U instead. Glad I was proved wrong by the RT-AX86U.
In my own home, when I first tested the RT-AX86U vs my 1-year-old RT-AX88U, there was no doubt that the RT-AX86U (even with 'semi-broken' Beta 1 firmware) was the superior model when the lowest latency is appreciated and wanted. When I had a chance to use two in an AiMesh network (around 386.1 Beta 2), I was sold on AiMesh v2.0. When I connected the two RT-AX86U's via their 2.5GbE ports for wired backhaul mode, I had to buy another router for my customer (the one I was 'testing' with was bought for a customer originally). The RT-AX88U was sold and is performing beyond expectations for a customer with ISP speeds of 1/3 of mine.
What makes the RT-AX86U better than the two-year-old RT-AX88U is the new 2.5GbE RJ45 Port (
all ports should be 2.5/5.0GbE minimum going forward), updates to the RF design, component choices, and no doubt, the under the hood programming/coding improvements that get the most from
essentially the same hardware (and that, just on Beta 3 or Alpha 4 today).
The router that most impressed me originally for everything, but particularly
the wired performance on the network was the oldie but goldie, RT-N66U (what a great introduction to Asus and RMerlin firmware).
The router that most impressed me originally for the range was the RT-AC3100. Great router for larger homes and/or slower ISP connections.
The router that most impressed me originally for network
responsiveness was the RT-AC86U, but that router doesn't support my AX client devices today (and for over a year now).
The RT-AX88U had all the above qualities and more, in one router. An interesting point is that with AiMesh (v1.0) and even 2 RT-AX88U's or an RT-AX88U (main) and RT-AX58U (node) in my home, I always went back to the single router in the end.
With a single, less expensive, RT-AX86U in my home, the network was now demonstrably superior. Higher throughput, lower latency, and as much reach/range as I need.
Why do I have two RT-AX86U's then in AiMesh v2.0 wired backhaul mode then? Because this not only gives me a 4 port, 1GbE 'switch' at the far end of the home (for 'free'), but it offers me my full ISP paid-for speeds (Fibre 1Gbps up/down, symmetrical) throughout the home wired or wirelessly. At least for my wired and my AX capable (non-handheld) devices.