If you think NNW is buggy, I think Gruml is quickly going to annoy you.
I really, really like Gruml in many ways. But it hangs and crashes far too often - like once a day on average when I was using it. After about two months with it, I finally uninstalled. It's still a beta, so I'm holding out hope that it will improve on that front by the time it's out of beta.
Then I tried Vienna, which I liked but does not sync with Google Reader. That only lasted a couple days. That turned out to be an ever bigger dealbreaker than I expected, so I moved on.
I've been back with NNW for about a month now and it's working well for me. I actually haven't had a single issue with it - not one crash.
So, for now, I'm sticking with NNW and hoping that Gruml will solve the crashing/hanging problem soon.