While I think this is a really good OpenWrt-router, with good value for money and easy installation...
It is fair mentioning that this model is discontinued from TP-Link and you will probably have to buy it second hand. It also comes in at least 5 revisions, with various levels of support, making life a little bit more difficult for the average, uninformed buyer.
As a side note: I have a 350mbps symmetrical FTTH link and I've had no issues maxing this line with regular, official OpenWRT builds.
Unless you need significantly higher speeds and can prove that official builds can't do it, I see no reason to go with unofficial, unsupported builds.
And it was flakey as f*ck. It rebooted itself roughly once a day, and would stop routing traffic to my fibre modem and need manually rebooted at least once a day.
The Openwrt support forums were... not helpful.
All this was such a shame, because the Openwrt feature set is so much capable than the stock firmware - I so wanted it to work, but had such a bad experience I haven't gone near it since and it will likely stay that way.
You have to be specific about the hardware you buy.
Throughout my time I've bought around 2 or 2 routers with the naive assumption "oh it will probably work out fine", and that's definitely not how it works. That has certainly left me with disappointment.
IME it pays off greatly to upfront research the specific model (and revision) and buy exactly that. Like in this case, the Archer C7 v2 (of which I've recently bought two).
It's running OpenWrt flawlessly and I would have zero issues recommending that particular model to anyone.
Ah, I got confused - it's a stock TP-LINK AC1750 Archer C7 that I have now, and it was an older TP-LINK I'd tried OpenWrt on. I forget the model, but I had been specific about the hardware I bought, making sure it was in OpenWrt's list of supported devices.
Strangely, the C7 I have now advertises itself as 'v2/v3'!
This build gets ~750 mbps NAT speed as opposed to vanilla openwrt, which is around ~300 mbps.