Next to perfect.  The only disappointment is the lack of color mixture in the flame.  However, the flame provides a fairly realistic presentation of the flame otherwise.
The variety of colors are mesmerizing ... 3 log colors and 3 flame colors provide 9 settings of choice or a selection for displaying all color combinations in sequence.  Mesmerizing, indeed, then there are the heat and fan settings; the combinations seem endless but we quickly noticed how hot the heater output was on the high.  That output will heat an average size room in fairly short order.
Installation was a snap.  We've had the unit 2 days now and still learning.  But we are pleased with insert and have no regrets at the purchase.  Recommend for anyone looking for a little relaxation especially after a hard day.