My favorite brand is TP Link. I don't know if it's just me but they appear to have most support for OpenWRT/LEDE. Availability is also a factor, I can order them from amazon and they arrive within 2 days.
841ND: It was the cheapest openwrt supported router. But FW size got bigger off late, so this has moved to 'tiny' builds. Not very useful anymore if you are adding any custom packages.
1043ND: Most widely available openwrt router with 8 MB flash + 64MB RAM.
Archer C60: My latest favorite. The cheapest 1350M dual band router which supports openwrt. It has same HW spec as 1043ND (except for only 100M ports, somewhat a bummer). Both bands WiFi has been pretty stable.. hopefully the known legacy WiFi issues with 1043ND are fixed in this.