I am curious the approximate run time differences between the 2.0 & 2.5 aH battery? I need to purchase another battery and didn't know if the 2.5 was worth the extra $50. I realize it all depends on what you are doing but are there any baseline numbers?
The 2.5Ah has about 2.5 / 2.0 = 1.25 or 25% more capacity, so one would expect the run time to be about 25% longer.
For example, if you are currently getting 30 min out of a 2.0Ah battery in a certain application, you could expect to see about 30 x 1.25 = 37.5 min with the 2.5Ah pack.