I switched my TP-Link TL-WR1043ND v1 from TP-Link's firmware to OpenWrt 15.05 "Chaos Calmer" a couple of weeks ago. Besides errors when trying to connect from PPTP clients, there were no unfortunate surprises.
I was happy to see OpenWrt now includes a web interface (LuCI) enabled by default. It is not exactly the user-friendliest, but I found my way easily enough.
Although I did not do much with it, I found a few bugs, notably:
The documentation is extensive, but its quality is poor. Installing while playing safe took me quite some time, though part of that was due to a bug in the previous firmware not accepting long filenames. Overall, I am not impressed, but I have no regrets. Coming from a bunch of volunteers, fair software.
I eventually realized that we have been experiencing "constant" intermittent wireless connectivity problems in 2 locations of the house. One of these is a decameter away from the router. The other is slightly more, but at the same floor and there is no exterior wall in between. At times, there was high packet loss and extreme latency. After discovering OpenWrt bug #12372, which possibly persists in OpenWrt 15.05, I suspected that our issue might have been a symptom of this bug, but the same problem persisted after going back to the manufacturer's firmware or to DD-WRT, so I ended up replacing with a TP-Link Archer C8.