I'm surprised there's no system that features integrated Homeplug[1], so base stations pass data to each other over your power lines. This seems like an obvious solution.
I currently am using a cheap docsis 3 modem (I believe it's a netgear), and an apple airport extreme for the main network, which is extended to the garage through a couple TP Link powerline networking adapters.
I haven't benchmarked the specific powerline performance, but I do know that if I hit up fast.com on my house wifi from my laptop, I get about 100-120 Mbps depending on the day and network conditions. (there's a lot of weird stuff with diff devices and diff routers that I'm eliding here but the Airport Extreme performs very well in my house compared to everything else I've tried)
in the garage, on ethernet to the TP Link powerline adapters, i get about 20 Mbps most of the time. It is pretty reliable, but it's a huge performance hit. Granted, I am using them in an extremely adverse arrangement: old wiring, running through lots of intervening hardware, through the ground, to my garage.
I'm actually happy with them, for my purposes, but they're really not fast.
fwiw, MoCA devices, particularly the new 2.0 stuff, have worked much better.
The results were mixed - they either work really well, or really badly. It seems that the home's wiring and appliances have an overwhelming effect on their efficacy. So, the recommendation is try before you buy if at all possible.
We recently just got a Netgear Orbi and are pretty well satisfied. Turns out the base router/AP is better overall than the other single unit devices we've been using until now and the satellite does seem to make a significant difference in the far top floor room which had problems with both WiFi & Powerline. Lucky for that, too.... our next step was to run cable in the walls.
The Orbi is basically the wireless equivalent of running wires through the walls.
You can have a mesh network without wireless clients at all if you wanted. For example, you can connect two locations together via a mesh of access points by each end plugging into the ethernet port of an AP, then the mesh provides multi-task redundancy.
Having said that, we had reached the point where I was about to call cabling guys to come in and just get it over with... which would have been some multiple of the Orbi number. We had also had various range extenders and bridges, etc. over the years and frankly I wasn't expecting much of the Orbi either.... but we've been pleasantly surprised with how well it's worked. The only complaint I have is that it does seem its configuration UI (web based) is rather sluggish at times... but I rarely use that.
At this point I think I can fairly say that for us it's been worth the price.
- always plug directly into walls, never into extensions, or multi plugs.
- don't even try to jump phases, performance will be atrocious but...
- if you have to, there are phase converters that you can install into your mains
There's a huge performance gap between cheap and expensive homeplug kits, and protocol implementation varies miserably between manufacturers. Also lowest speed adapter determines network speed.
So ideally you want to buy Devolo or TP-Link Homeplug AV1200 kits with integrated power outlets, stick them into walls directly and you can absolutely get a solid Gigabit without running cable through walls.
I do absolutely agree that troubleshooting is a horrible pain however.