hmmm good question.... I believe it boils down to discharge rate, power, charge, amps.
In my opinion all are good in their own application, I myself use lipo's. My reason is the discharge(how much power the unit receives at one time) rate and weight is by far more Superior to any other type of batt. Down fall is if your not careful with running your batt to low, over charging or puncturing you can damage or explode your Lipo's, destroying your rc or what ever it's sitting on at the time.
Some esc's will only allow you to put a certain amount of power through the unit and will not require a Lipo so 6-7 cell nimh batts will do just fine(crawlers/scalers)
Not to sure if this answers your question completely, but this is my understanding about some of the batts info that I know of. I'm not a batt techy tho