So, my old TP-Link WDR4300 router died after nearly 7 years of full 24/7 service and I'm looking for a replacement. As this happened suddenly and considering it was my main router, I'm currently limited to what I can find on local stores, since the shipment of anything bought online will take ages due the pandemic we're currently living.
The most common hardware combinations within my price range that are readily available where I live are either MT7621AT + 2x MT7615N (D-Link DIR-878 and DIR-882) or MT7621AT + MT7603EN + MT7612EN (Xiaomi Mi Router 3G and Mi Router 4A) or some very very old models that, while not inherently bad, seems like a waste of money to buy new nowadays (TP-Link Archer C5 and C7).
I'm inclined to go with D-Link because they have official support channels where I live, unlike Xiaomi, which doesn't sell anything officially here, so you're basically on your own in case you end needing any kind of technical support (RMA, warranty, etc). Having essentially a locked bootloader and needing to rely on hacks and exploits in order to flash custom firmwares is another reason to drive me away from them.
I'm aware there's currently no official OpenWRT support for neither DIR-878 nor DIR-882 other than an open pull request for DIR-878, which reportedly also works on DIR-882 since they're essentially the same device (apart from the lack of USB ports on DIR-878) and I'm willing to help bringing official support in case I end getting one of them (likely the DIR-882 since I do have use cases for the USB ports).
What concerns me, however, is the current status of the mt76 driver, as I read lots of conflicting information. What I could gather is that mt76 is a kinda new driver that hasn't been mainlined yet and you might experience all kinds of bugs and instabilities with them depending of the specific MediaTek chip, is that accurate? Looks like it's also possible to use the proprietary, non-free Mediatek drivers on OpenWRT with some effort too, but I would rather avoid that.
TL;DR since I'm probably getting a DIR-882, what's the current status of the MT7615N when using the open mt76 driver? How does it perform, for example, when compared with the proprietary drivers?