Minera is indeed very good, but it's still very unstable, and has been like so in the last versions. Things I've been noticing:
1. If I save new settings and restart, minerd hangs randomly, while setting chip frequencies
2. Also, when I save new settings and restart, it sometimes starts hashing but does not accept any shares
(to solve all of the above I have to restart several times till it works)
3. when I add 3 or more pools, it gives errors similar to 1 and 2, and the only workaround is to remove those pools from the config
4. Pool switcher rarely works
Anyone experiencing the same? Any workarounds?
the miner hanging when you set saved frequencies is a known problem
the other stuff seems to be a feature of cpuminer that or duff usb hubs (mine seem fine since I ditched the cheapo ones) a reboot is the best bet.
Oh and I have had little success with my 40 chip blades which seem to hang with minera if it's blades you are using use hashra or a as I have low power netbook and bgminer