Milwaukee is worth every penny.
Fyi if you happen to need to power your black and decker liion or dewalt liion, but you dont want 3 or 4 brands of batteries, amazon sells adapters from m18 to the other liion packs in the same voltage range. The m18 is the same voltage as dewalt 20 and b&d 20V. That way you only have a handfull of milwaukee batteries that get used all the time instead of a bunch of different brands that never get used and degrade over time. You just need to take the m18 out of the adapter and charge it with your milwaukee charger.