I've been using TP-1043ND v1 and v2 for years with OpenWrt and it has been prety good.
However, my main router (v2) is now showing signs of its age, so I'm wondering if I could find in black friday some sweet deal to replace it.
Last year I bought a Netgear N7000 without asking opinion here and the result was that it's not fully supported in OpenWRT, so this year I don't want to run into the same mistake.
Having this in mind, I'd like to ask for recommendations taking into consideration the features I use:
USB, which allows me to:
Have rootFS on a pendrive and having several sw such as openvpn, knockd, DDNS, my scripts, opkg, etc.
Monitor a UPS
Have a 3G modem to send sms
Interfacing with an arduino (use-serial comm)
Gigabit Ethernet
VLANs
Virtual WIFI (I have a second wifi interface bridged to the WAN interface, for guests)
TP-1043ND radio is 2x3. Maybe we could have something better? 5GHz WIFI is not a strong requirement.
Between that and the Table of Hardware, you should be able to narrow it down and start looking at device-specific threads, or asking device-specific questions.