IMHO using a metronome is not just about increasing speed and/or accuracy, but reducing the need for it altogether. That's why I prefer a simple tic/toc. For me, the speed can be increased gradually to help perfect execution, but the interval of the beat can also be increased to help the inner sense of timing. Once comfortable at a particular tempo, try setting it to just the downbeat of each measure and see how you do, or every 4 bars if you're humble enough. Or, just set it to the 2 and 4 (backbeat) and use it that way. Drum loops are great, but I find I tend to be more sloppy when hearing all the subdivisions rather than internalizing them. Just my .02.