To preface, I don't think a small office needs business class router more than Bob's apartment, I just think Bob's apartment should also be running a business class router.
I like the Pepwave Surf Soho recommended on the site I linked. Config is through a web interface like a consumer router, end user experience for WPA2 is the same.
If you want to save some money, consumer routers that you can flash with OpenWrt should generally be fine, the TP-Link TL-WDR3600 is very cheap, the TP-Link Archer C7 is also good. (Though several versions, so sort out which version you're ordering and whether OpenWrt has support for it.)