I've been using the Tama Rhythm Watch metronome for a number of years now, and I'm pleased with it. I used to have the old model Dr. Beat for many years, but gave it away to a needy student.
The Tama Rhythm Watch is nice in that it you can set-up 20 different tempo presets, Tap Tempo, two different click sounds to choose from, two flashing lights that cycle back and forth, a PHONE OUT (mini pin), and a Master Remote 1/4" jack which allows you to plug in a regular box type foot switch .... so you can cycle through your tempo presets without using your hands. It also has the standard subdivision dials so you can add eighths, sixteenths, eighth-note triplets or accented downbeats phrased anywhere from 1 to 6. The Rhythm Watch runs off a standard 9-volt battery or optional wall wart power supply.
It's been a reliable metronome and has made through many a gig/session for the past 6 years. Another cool feature is that it has a thread fitting which allows you to mounted on a cymbal stand. The only drag is that you have to use a TAMA stand (I use a boom arm & clamp) because of the threading. So be prepared to pick up the additional boom arm if you don't already own some TAMA hardware.
I take my Rhythm Watch with me wherever I go; it stays in my stick bag; a tool for my gigs or sessions. It can even be my attorney if others in the band were to think my tempos were not right.