Those results are consistent with Apple's latest earnings report. The company said its Watch and TV sales jumped up 31 percent year-over-year, and head honcho Tim Cook said Watch sales have nearly doubled since last year. Neil Mawston, Strategy Analytics executive director, said Apple's Watch Series 2 has been selling well "due to enhanced styling, intensive marketing and a good retail presence."

On the other hand, there's less and less demand for Fitbit's bands, perhaps due to the increasing number of sports-oriented smartwatch options for buyers, among other factors. Its attempt to enter the smartwatch market was also late and quite underwhelming. While Fitbit still sold the most wearables late last year, it was already in trouble by the beginning of 2017. It had to cut 110 jobs in January, which might not sound like much but is still 6 percent of its workforce. In an attempt to recapture part of the market it lost, Fitbit is reportedly preparing to release a new smartwatch and a pair of wireless headphones in the fall.