I guess this is the place for this. I'm working on some software for rhythm training just wondered what features people would look before beyond a standard metronome, both to work through with students and for solo practise?
Well,
if it's for sax players, make sure it is loud enough. Many standard metronomes are not loud enough to be heard, especially when practising soloing. Also, make sure it has a pleasant sound. It should be a deep "clack" rather than something that reminds you of the alarm on your digital watch. There are some credit-card-sized metronomes out there around 20 Euros that have that kind of sound. I don't know anybody who is really pleased with them.
As for features: I like the accent on the first beat in a bar, adjustable volume, different bar measures, LEDs in addition to the sound. The rest does not interest me so much. I had a Boss Dr. Beat in the 80s. It spotted off-beats, triplets, eights and sixteenths. I never really used these features. They were rather distracting. The good thing was that it started at 35 bpm and went up to 250. And it was loud enough.
I'd focus on usability, that is, avoid multifunctional keys, whether real or virtual ones. Also, a smart phone does not seem to be the device that you can get a pleasant sound out of, just because the speaker is too small. Furthermore, I would not like to boot a laptop or tablet PC, then launch a program or an app to get my metronome started. Just too much hassle to get going.
Functions beyond those found in most metronomes today: nothing really.
I hope this helps.