Product review (3 stars): Pleasantly surprised, only slightly frustrated.
My wife and I researched induction cooktops before buying this one.  I would suggest anyone unfamiliar with induction cooking to familiarize themselves before buying one.  If a magnet sticks to your cookware, then that will work with an induction cooktop.  Some of our favorite pots won't  work with our new cooktop, but we knew they wouldn't before purchasing.
  This thing is incredibly fast.  The first thing we made was tea and it had the water boiling much quicker than the old conventional electric coil cooktop.  I got an error ("E") when playing around with the burners, but my wife informed me that that was because there were no pots on the burners yet!  Once I placed my (ferromagnetic) teapot on the appropriate burner, I was allowed to power that one on and boil water!  This thing works much faster than I was expecting.  We really disliked the old cooktop, so this one didn't even need to be that great to impress us, though.
  The reason for rating this four out of five stars was the instructions that came with it.  With so many things being made in China (and with the price so low), I've come to accept and maybe expect slightly inferior documentation.  This cooktop only came with a user manual.  It didn't include anything that would explain how to install it before using it!  I tried looking up Windmax online for better instructions, but had no luck with that.  The wires sticking out of this unit are green, blue and brown.  I was confused as to how to hook this up.  The old GE cooktop had red, black and bare wires which are pretty standard, I think.  Our house wiring has red, black and bare wires for this appliance.  What I found to work was connecting the bare wire to green, our black wire to blue, and our red wire to brown.  Some type of diagram with the cooktop would probably have earned this five stars.

Update 2/22/2016:  After using this cooktop for some time now, I've felt the need to lower my rating from four to three stars.  My dissatisfaction with this unit is when using it to simmer.  When the power is at 1 or 2, it seems that it produces high power (9) for short bursts.  Rather than a slow simmer, you get a rapid boil for a few seconds, and then nothing.  I'm not sure if this is how induction cooktops work from other manufacturers, but it is an annoyance when trying to work with low temperatures.