which is better ..?

i see various designs on the little stoves ...some say to use alchol some say denatured alchol...which is better which is hotter

Denatured alcohol is usually ethanol that is not safe to drink. That is, it has impurities that make it unsafe.

Ethanol (aka ethyl alcohol) is the alcohol found in many popular beverages.

Any type of commonly available alcohol (denatured alcohol, 90% isopropyl, methanol aka HEET) should work well in an alcohol burning stove.

A problem one might encounter would be using an alcohol with too much water, such as rubbing alcohol or most hard liquors. They might burn, but they won't burn as efficiently as a purer alcohol.

Yeah, what PerryMK says-

I would add that rubbing alcohol is 70% isopropyl. Even 90% burns sooty and stinks, but in a pinch they work in some stoves. I've added samll amounts of water to burning stoves to decrease cooking temperatures. It is a little tricky, but can work.

CamperMom

Alcohol:
Ethanol = grain alcohol: 'Everclear' and other potable pure alcolols are 90+ percent and work great in stoves, burn hot and clean. Problem is expense. Other spirits for drinking have lower concentrations.'Proof' is 2X the percentage of alcohol. 100 Proof is 50% alcohol, 80 proof is 40%. Bourbon and other flavored/sweetened liquors will leave sticky deposits in the stove and are very inefficient as fuel.

Denatured alcohol is ethanol contaminated with methanol (methyl alcohol) which is highly poisonous, or a bittering agent such as rubber which makes it undrinkable (liquid Sterno). It burns clean and hot and is relatively inexpensive. Look for cans labeled 'lacquer thinner/marine stove fuel' at paint and hardware stores. Avoid Sterno. It is usually 40 percent water.

Pure methanol is usually found in the form of yellow 'Heet". It burns clean and hot, and is available on most stores that sell auto supplies (rural convenience stores). It is also sold as a solvent and thinner in cans at paint and hardware stores. Under certain conditions methanol (like all alcohols to some lesser extent) produces formaldehyde.

Isopropyl, 'rubbing alcohol' comes in concentrations as high as 90%. It burns with a smoky, greasy flame, and really messes up the pot. Some stoves don't like it. Theoretically, isopropyl contains more energy than the others, but few stoves can take advantage of it; the carbon deposits it leaves are evidence of inefficiency.