...no longer in production (or for sale) since late 2015/ early 2016.
They've been solid devices and there's no reason not to keep using them, but buying them today would be a bad idea (you can't get them new anyways and used they are typically overpriced (they tend to sell for more than what they were worth new from the factory) for what they can offer), making them a bad suggestion.
Based on the OP, my answers were valid. They are a good cheap choice, if you can find them. They are both very stable with 18.06.2 and they have plenty of memory. I bought them used @ 20€ a piece. As an added value, the open source uboot is available to them.
Archer C7 (the real one, not rebranded C5) is another good choice. However, we are stuck with the Chinese language, closed source BREED bootloader, which they claim is not a u-boot mod (which it is, and the source is closed as well) which basically does not support command line arguments, setting the MAC address in the menu reverts to generic driver etc (you can see this in the UART post when router starts).
I've started my OpenWrt adventure with Linksys WRT54GL. It was (still is) a very cool router.
Afterwards I had a break from the Linksys family, for some time I've used ASUS RT-AC68U which unfortunately is not supported by OpenWrt (Broadcom wireless doesn't work).
Next setup was somewhat different - Cisco ASA5520 FW + Cisco Catalyst C3560G Switch + Cisco CAP2602i Access Point. This setup performed very well (iOS is quite nice if you're patient enough to master it) although even after replacing the fans with Noctua's silent ones and running them slower than they did by default, the setup was quite noisy and very power hungry.
At the moment I'm running OpenWrt on Linksys WRT32X with small 8-port Cisco SG250-08-K9-EU managed switch for VLAN trunking and tagging and it's a totally awesome setup which I can highly recommend to everyone.
It does mean that four ports which come with WRT32X are definitely not enough for my environment Port 4 on the router to which the Cisco switch is connected is set to 'trunk' mode and selected VLANs are passed through it. Thanks to that I can decide which ports on Cisco switch are assigned to which VLAN. That would not be possible if the switch wouldn't be managed.
I own both the archer c7 and the mir3p. I can say that i enjoy using the mir3p more because of the usb 3.0 ports that comes handy when i attempt to host a ftp server for media purposes. mir3g/mi4a are similar and good devices too.
Also, how does not having a GigE port make the wireless features useless? 100Mbps ethernet actually hits 100Mbps under typical conditions. 866Mbps WiFi rarely even reaches that speed for the payload of a packet, and it NEVER sustains that speed due to the requirements of the protocol. 100Mbps may still be a bottleneck at times, but not so much as one might think.
Xiaomi Mi Router 3G (ramips/mt7621/mir3g) is very solid with 3xGbE and 2x2:2 802.11ac, plenty of RAM and flash. The only downside is not enough Ethernet ports, 4 or 5 would've been much better.
Or, as of lately, Xiaomi Mi Router 3 Pro (ramips/mt7621/mir3p) is very promising as well because of recently added support for MT7615 (it's already in trunk! but still very rough, Tx is 2-3 times slower than mir3g's MT76x2).
WikiDevi lists them as follows:
Broadcom-based Mi Router Pro = MiWiFi (R2D)
Qualcomm-based Mi Router Pro = MiWiFi HD
Mediatek-based Mi Router Pro = MiWiFi Pro
From what I was able to gather from Xiaomi's website, they are all called Mi WiFi Pro, and all have Mi WiFi HD variants, all of which which hold 1TB of storage.
Are you sure that's not some marketing-speak that you mistranslated? This is the first time I hear about this nomenclature. But you are right that there is no "Mi Router 3 Pro", it's just me extrapolating from OpenWRT's "mir3p" board designation.
Regardless, the Qualcomm-based "Xiaomi MiWiFi HD" (I'm using WikiDevi names), with dual QCA9980, is indeed very interesting. If the specs at WikiDevi are correct, this may be my next router if/when I get tired of waiting for fully functional mt76, thanks