While a lot of fitness tracker companies struggle to make devices that combine the best of all worlds, others are sticking to what they know. Mio has been making heart rate monitors for years—most of its trackers are not the most comprehensive or the most stylish, but Mio knows heart rate, and it's sticking with that.
The new $130 Slice fitness tracker shifts slightly out of Mio's comfort zone while still mostly focusing on heart rate. It has a few extra features, including daily activity and sleep tracking, as well as smartphone alerts, but it uses Mio's optical heart rate monitoring technology and PAI point systems to assess your fitness level on a weekly basis. It's clear Mio sees the need to modernize its lineup with the Slice, but it also has to convince users that a one-trick pony can be just as good as a multipurpose device.
from Mio Slice review: Heart rate done right, but style is still a struggle