Last weekend I prepared some sautéed yam for some guests. I usually prepare it in a non-stick steel pan with thick bottom, and I have to be very careful in flipping it at the right time to avoid charring it too much. This time, since that pan was being used, I had to use a non-stick aluminum pan with thin bottom, all the rest being the same. I was concerned that it would char even faster, instead the cooking was slower and more homogenous, resulting in a better result. I always thought that a thicker bottom would allow for a better distribution of the heat. Is this not the case? 
Aluminum conducts heat better than steel.  This means that, everything else being equal, an aluminum pan will have more even heat over the whole pan than a steel pan will.  This is also the reason why expensive steel pans generally have an aluminum disk sandwiched into the base. I suspect that, knowing the pan was thinner, you used a lower heat on the aluminum pan, resulting in more even and slower browning. 