I've only just started using this as of last Sunday - but so far, I love it. Like all Pureology products, it is very lightweight yet effective, and, of course, sulfate free/alcohol free. It also had a generous amount of protein, which is a godsend when flat ironing damaged hair. The smell is pleasant, and the product absorbs into the hair quickly.
The only qualm I have about this is that too much can come out if you press on the nozzle too hard - so watch out for that. Personally, I find this product works best when spritzed into my hands; this way I can control how much is applied to my hair and completely avoid the heavy feeling this product can give when too much is used.
I will update if I find that my position on this has changed - though I have yet to find another heat protectant that doesn't wreak of alcohol.
Will be repurchasing, but I doubt I'll have to any time soon considering how long this stuff lasts!
UPDATE: I find that the packaging of this is becoming more and more irritating to me - it sprays in one squirt, not a fine mist, so your hair is left feeling heavy and over-saturated. That said, the product itself is still great, so I just poured it into an empty spray bottle that I had from a previous product, and it completely solved the problem. If you're going to buy this, have another spray bottle on hand!