I understand your frustration. I'm not using this router (WZR-HP-G300NH) anymore for anything other than a toy.
It was a client bridge for me, but I got tired with the Buffalo branded 14998 and it's constant wireless crashing.
Now I'm using a cat6 cable with gigabit switches instead.
About the router...
It definitely seems to be performing better now after the update.
Steady 270TX/270RX wireless connection, no hanging yet. I think this combination might just work.
Let's see...