Remember that if you go with the 4x rechargeable AA options, you will have 4.8 volts as opposed to 6 volts with the 5 cell hump pack. This may not be a problem if you have a really good steering servo, but if your servo is on the weaker side then the more volts the better! Tho you will get longer runtime with the AA's.

1600mah compared with 1100mah is about 20% more runtime actual figures are very hard to quote as it depends on how much current draw you have from your servos.