Nikon and Canon are equally good and I doubt that changing brands will make any difference to your results. There are many reasons that you could be taking blurred photos, including wrong selection of focal points, assuming that you're using autofocus, or a viewfinder that's wrongly set for your vision if you're focusing manually. And a big culprit that causes blurry photos is camera shake. Are you shooting hand-held in really low light? If so, are your lenses stabilised? And when you're shooting in low light do you use high ISO settings to reduce the exposure time? The problem could be something else, but checking these things may be a good place to start.