I frequently see guys complaining about uneven burn. Here's a brief summary of a post I made on another board:
Uneven burn is usually due to one of (or a combination of) the following factors:
1. Smoking too quickly, discussed above. You should wait about 1 minute between puffs. The cigar will burn cooler, taste better, and last longer. With a proper RH, the stick shouldn't go out between puffs.
2. Uneven humidity levels between the wrapper, binder, and filler. Different leaves hold moisture differently. For example, ligero is a very thick, roughly textured leaf which holds a lot of moisture (relative to other leaves.) Since ligero is frequently on the inside of the stick (you can sometimes see this at the foot - ligero is very dark after fermentation, almost black), it will take longer for the moisture in the ligero to equalize(relative to the wrapper and binder) to a proper smoking RH. "Wet" ligero tastes "peppery hot," or like tobasco sauce. To me, it tastes unpleasant compared to when it is at a proper RH.
3. Poor quality tobacco/inexperienced rollers, especially in big ring gauge cigars. Only the most experienced rollers have the talent to roll the big gauges. If a particular brand/size that you smoke is constantly burning poorly, then it's the fault of the manufacturer(assuming #s 1 and 2 don't apply.) You have to decide if this is a problem to you - if the price is right, fine, otherwise, ditch that brand. Life is too short to smoke crappy cigars.
I frequently see guys complaining about poor burn due to an improper/uneven cut or a poor light. IMO, cut and/or light doesn't affect the burn. I've thought about all the times that I got a really poor cut/light while driving 65 MPH, talking on the cell phone, etc....and got an even burn. So I decided to experiment, using quality cigars that have been reliable in the past. I cut them at severe angles, lit one side of the cigar, lit a cigar by inhaling the flame, etc....things that you really shouldn't do. Guess what - in my tests, it doesn't matter. The cigar may burn unevenly for the first inch or so, but it should catch up by itself. I know there will be some who disagree with me, but try it for yourself.
Hope this helps.