The guys at our regular session have 4 between us, and find them the most convenient of what is on the market to use.
They seem to function better when plucked with the thumb or finger , rather than with a pick.
I use them a lot for tuning up my mandola, and other paired string instruments. the only drawback being getting the two strings identically tuned, it's easier to set up the first of the pair with the tuner, and then tune the second to that string at times.
The guitarists in our crowd swear by them, and don't seem to have this problem. (also fine for banjo and fiddles) I would recommend them