Product review (3 stars): Temp accurate, humidity not so much
Temperature seems to be spot on - but humidity fluctuates in accuracy a lot.  I purchased this because we were having problems with our HVAC at work.  When the HVAC tech put his humidistat next to this one - it varied between 5% and 15% lower than what the Vics humidistat was showing.

It's a good guage to give an idea of when humidity is going up and down, but it's not accurate.