As to stability, I'd describe it has a mixed bag. I owned one for just under five years and had to do fortnightly restarts (which I eventually automated), and we also owned one at work which needed nightly reboots (DD-WRT provided that).
PS - In fairness to the work one, the building was insanely congested. It was one of these buildings which are shared by three dozens small businesses, and each had 1-2 WiFi networks, plus the local homes also. When you spun up a WiFi analyzer it could not find an empty piece of spectrum, and a lot of routes/APs would crash if you left the "find best frequency" option checked (as they would hop continuously and never find anything).