One question I would ask of those not happy with hook performance, is were you using a decent hook? I have tried a few of the basic models with a razor blade, and found their performance sub-par. Same for the knives with a slot in the handle, to expose a small area of the blade to serve as a hook.
The first one that I truly liked was the hook on the Gerber-made, Hinderer Rescue Knife. Not surprising that Rick Hinderer could design a decent knife as he also happens to be a volunteer firefighter. I used and carried that knife for a while at work and liked it, but it had a few compromises I didn't like. The hook was small, but very sharp when delivered. Unfortunately it's design led to some difficulty sharpening it after using for a while. I also found the knife to be a bit bulky for what it was, and the dull point (designed for prying) and full serrations minimized it's use as a general purpose knife. The window punch on it worked, although being steel it rounded off after a few uses (Really this is an emergency feature, use a carbide tool if you can.)
The Kershaw Funxion EMT also has a hook on it that I have used several times. It is more open and I find a little easier to sharpen. It is also a combo edge and clip point knife design, leading it to be capable as a general purpose knife with a hook if needed. The window punch on it is also carbide and shows no damage after use in a few training drills. At the $25-$30 street price it is cheap enough to carry and not worry about loss or damage. The fact that it includes a bottle opener in it means it finds it's way into my pocket a fair bit off duty as well. If they made a similar, but upgraded material version at about $60, I'd be in love.
But, by far the best hook I have used is a Benchmade Rescue 5. I received it used, as a gift. My Best Man had used and carried it for several years in several very busy EMS only career services, and spoke highly of it. When he left that line of work while in med school, he passed it on to me. Even in a used state it blew away the cheap razor style knives. Sharpened up, it is a joy to use.
Anyway, back to the topic of a high end rescue hook, I completely forgot about something that
may fit that description that a paramedic/emergency room PA friend of mine told me about a few years ago. The S-CUT from Sweden. I remember thinking it was great, but something I wouldn't spend almost $200 on.
Review from Emergency Physicians Monthly:
http://www.epmonthly.com/departments/subspecialties/technology/swedish-s-cut-trauma-shear-a-cut-above-the-rest/
And the following conclusion from a study published in The American Journal of Emergency Medicine (hosted on the manufacturer site): "We found that a new device (S-CUT) used to expose the chest in OHCA was associated with a reduction in procedure time as compared with scissors. With regard to the types of clothing that were expected to be most commonly used, the mean difference was more than 20 seconds for indoor clothing and more than 1 minute for outdoor clothing.
http://www.s-cut.us.com/pdf/Scut__Aune_et_al.pdf
They have a few other studies posted there as well, and their results reflect my personal experience with a good quality hook, like the Rescue 5/7.
As I work for the government, and have a family to support, that is a little rich for me for a single purpose tool. If you have the money to spend...