This is replacing a Yox water flosser that lasted a year after being used multiple times a day. The power button on it shorted out. This Waterpik is almost double the size and the water stream is around 60% more powerful. The unit is slightly heavier as well. Those are the tradeoff's between the two, size versus performance. I expect reliability to be about the same based on other reviewers.
It's exactly what I wanted and works great! It's portable, great when traveling, and a very expensive way to keep up with your oral health. It also has 3 speeds.