I have one of the Linksys WRT-AC series (WRT-1900ACS but they are all pretty similar I think) - they're very well supported by OpenWRT (stock firmware is a deri

I have one of the Linksys WRT-AC series (WRT-1900ACS but they are all pretty similar I think) - they're very well supported by OpenWRT (stock firmware is a derivative of OpenWRT in fact at least on some of them). Hardware specs are good, including reasonably fast CPUs (good enough to saturate a VPN at 100Mbit at least which is the uplink I have here). The open source wireless chipset support is towards the better end too - not perfect but a lot better than some others. If you're flashing your own images of OpenWRT, there are a few conveniences which are a bit more uncommon in the hardware which are useful if you ever need to debrick - eg easily openable case, UART header comes pre-installed (you don't need to solder your own), etc.