i have several for different uses, i.e. i have a large mechanical seiko metronome for home use on my instrument that doesn't leave the house. i also have a nice old eletronic premium seiko portable one with a headphone jack for travel/practice outside i.e. practice rooms, rehearsals etc.
i just got a nice wittner piccolo mechanical metronome that will probably serve as my main portable metronome (the seiko is from my music school days and i'll probably retire it to back up status or only for headphone use i like mechy's much better ).
also if cost allows it i do reccommend the wittner, properly used and cared fore i have heard and seen of these lastings decades and they're probably the best of the best overall. the large home use pyramid ones in wood are super expensive though.
i like the seiko's as a good mid range i.e. best quality for the middle price point. i advise against 'no name' or cheap asian models (i.e. some of the chinese knock offs, i've read only of problems with inconsistent manufacturing quality, bad mechanical movements, etc.).
the download of the free metronome app is really good if that's all you can do. i think there's an inexpensive steinway app as well but i don't see how it woudl be better than the free version.
if you want a picture of the model number seiko i have i posted a metronome question recently
https://www.pianostreet.com/smf/index.php?topic=44323.0if you're in the eu or asia you should be able to get it, it's not wiedly available in the us i had to import it.
Topic: Metronomes!