So if you do not have any cordless tools the Dewalt should be at the top of your list and get the 60 volt batteries. But buy the higher amp hour batteries and you will get long run times and fast charges.
Before buying the higher amp hour DeWalt (and Milwaukee, for that matter) batteries blindly... be sure and go to a bricks and mortar store that actually has these huge honkin 60v and 12 ah batteries in stock, and ask for an associate's help in unlocking display models so that you can heave and hurl the heft of your tool of choice with those larger batteries installed. The difference is H U G E, most noticeably in size, making the tool less nimble to use within tight places and clearances (inside cabinets, etc).
So an inventory of smaller sized batteries would be advisable for everyday work.
I have zero interest in promoting or denigrating one tool brand from another, but I can share that I recently changed cordless tool brands, and one of the considerations that factored heavily in my decision of which battery brand to pick was functional ergonomics in close quarters. The other considerations were:
- Form Factor Power Density... the density of amp hours per cubic cm of battery pack
- Form Factor Power Distribution... the distribution of battery bulk and weight as configured on the tools I was most likely to use.
- Power Cost Ratio... comparative cost per amp hour, using online tools like camelcamelcamel, combined with my own shopping experience to compare battery pack costs over a 2 year period to include periodic and seasonal sales. My target for Lithium Ion has been $12.50 per ah, which thus far I've always managed to meet.
- Interchangeability and Integration... can the batteries within a brand work in all tools interchangeably (not just in fitment, but in ergonomic function)
- Portfolio of tool solutions... does the brand offer a tool solution that meets my needs in the shop, on the job, as well as outdoors in the yard
So for me, the decision wasn't about getting the biggest battery... it was more a confluence of factors that helped inform my choice. And ergonomics was a major factor.