The best answer to this is to try it out. Buy a pack of 4 to 5 different types of bubble gums and have a few friends "sample" each one. Have them chew and blow bubbles of each brand (one at a time) over the course of a day. Ask them to record how long the flavor lasted, if the bubbles were as large at the end as at the beginning, and how tough the gum got at the end. Repeat with another brand on another day. This may take all week (or longer since most schools do not allow gum chewing during the day), but it should be interesting to find out for yourself. Also, you will have scientific evidence to support your claim!