I've been using it for approximately 2 years now.
Sadly, I haven't had the opportunity to use it's stereo option on two different speakers, but using its mono output, I'm very satisfied.
The rate goes all the way from barely moving (I'd say 0.2 Hz) to rapid pulsing, which rather than tremolo sounds unusual, especially with the depth on maximum and square shape, that way it sounds "farty", and it sounds as if two frequencies are played at once. Nice for experimenting.
The depth is a confusing feature once you go past maximum, which is somewhere just over half of a turn of the knob. The only thing I wish here is that the knob would "slip" into the position for full depth, because it's sensitive and sometimes it's hard to set it to full depth and not go over. This is particularily hard if you want to change setting during a song or when using a low rate, but if you aren't in such a situation, it will again offer lots of experimental sounds you can not obtain with regular tremolos.