My experience from using iStroboSoft has been so far excellent. It allows me to tune my mandolin very easily and very accurately. It is actually so accurate that it can be used for intonation. If using an iPhone for tuning is ok for you, I believe this tuner will become your best friend.
No need to carry additional device, besides your own Apple device
Extremely accurate chromatic tuner
Noise filter and input boost allows you to use it even at noisy environments.
Suitable for many instruments, including Guitar, Bass, Banjo and of course the mandolin.
Costs less than most digital tuners in the market.
Not a clip-on tuner, so not live-performance friendly, especially for soloists.