My litmus test for whether I like a device or not is if I still enjoy using it even when it has the occasional issue. My Lumia certainly has a few teething problems - probably one random shutdown a week, a weird autofocus thibg on the video camera, and the occasional power on/off cycle needed to hook up wifi, and I *still* think it's fun.
The OS still needs a few things, the hardware isn't bleeding edge, and the app support isn't as good as other OSs, BUT the whole is much greater than the sum of the parts (which I think is probably true of most Windows Phones).