These will be great, IF you get them professionally molded and ensure you get the right size for your boots. Read the info on Intuition's website for sizing based on your boot size (esp if you have .5 boots since these only come in .0's).
We tried to heat these using the at-home methods online, but weren't overly successful. If you insist on doing it at home, put them in your oven, use a laser thermometer and be sure to add plenty of extra socks for toe space. I recommend going to a ski shop to get them professionally done, though - it's worth it.
Disclaimer: these were a gift for my boyfriend, an ex-ski racer, and he thinks that they are not as stiff as a stock liner (contrary to the reviews below). Stock liners have a hard plastic tongue, and these do not.