I use two. Both free. MetroTimer and Pro Metronome. Why two? Because I am lazy. The MetroTimer is always left in 4/4, Pro Metronome is always left in 6/8. I play a lot of Irish music but it takes several keystrokes to convert either metronome from 4/4 to 6/8. If you really want to use just one Pro Metronome seems easier to adjust and set up. I often convert it to 9/8 for slip jigs and hop jigs. I may simply think it is easier because I change it more. MetroTimer has been in 4/4 from day one.
MertoTimer has an easier timing function, if you want to set it for two minutes or three minutes or whatever. That might be more useful for a drummer. Pro Metronome does have a timer and it works, it simply takes a couple more keystrokes to invoke it.
updated by @pondoro: 11/02/18 09:15:38PM