I use Nuby Hot Safe Spoons to feed Andrew his cereal (around $4-$5 in most baby/drug stores) and I'd rate them as just "OK". As an ordinary baby spoon, they get the job done--they're soft tipped to be gentle on baby's gums and have a long, ergonomic handle to reach deep into food jars. But, the fandangled hot safe feature just doesn't work that well.
The white tip of the spoon is supposed to change color after being in too-hot food for 15 seconds, but the color change is so faint--a pale pink--that I'm never quite sure if the color is there or not. I've tested the spoon in hot baby food (no color change) and even put it into boiling water, which elicited a faint color change for about a second. Not quite the dramatic hot safe feature I was expecting!
So, the spoons are just fine for feeding, but don't rely on the color-changing feature to determine whether food is too hot for your little one (go ahead and taste that delicious pureed meat yourself!) Its just another lesson that, regardless of a product's advertised safety features, you need to be the last line of defense for your child.
Pureed meat, here I come!