are the worth the money? and do different brands perform different

if you get the ones to absord shock then yes.... I get the ligtest ones I can find. Right now im using a Carbon Impact Quad which is light but absorbs vibration. Limbsavers makes quite a few

If you go to a shop, test them out by dropping them on there head on the counter. If they bounce they are no good. If they dont bounce then you know its absorbs shock

I dont shoot any better with or without one though if that helps answer you question

Yes and yes. Hunting or target? Look at these: www.deadcenterarchery.com

Yes, and it depends on what type of bow you have what may be best. If you have a parallel limb bow, more or less all you'll be doing is absorbing a little shock, not really much stabilization needed or gained on a parallel limb bow, but if you have flexed limbs, then a longer stab with a little weight on the tip makes ALL the difference in the world. I use cheaper stabs and they feel as good and seem to do as good a job as the more expensive ones I've tried out. Eastman Carbon Rod Stabilizers are on all 3 of my shooter bows. One of which has a Sims S-coil on the fore end for a little extra weight, and shock absorbtion. Shoot a bow with one and without one, and you'll likely notice a BIG difference.

they do work, and they are worth it. I use the Limbsavers S-Coil too. I shoot a bow with little vibration though. It depends on your bow which one you should shoot. If you shoot a bow with alot of vibration you might need a more advanced stabilizer. But either way i would get one.