I have invested a fair amount into both Makita and Milwaukee. I have a set of batteries on my Makita that are still running STRONG a decade after I bought them and they still hold their charge over a long period of time.
I invested heavily in the Milwaukee 12v, 18v and 28v li-ion systems as well about a decade ago. Almost all of my batteries are toast anymore, mostly from me not keeping up on consistently charging them when not in daily use. I know that batteries loose their ability to hold a charge over time, cells die, it happens... and I don't mind buying new batteries, but Milwaukee's shift from the v18 to m18 tool series with a completely different battery base was rather frustrating, as it made a significant investment on tools virtually useless.
Outside of my frustrations with some of Milwaukee's choices on the direction of their battery systems, I have been extremely impressed with their tools overall. Their 28v system produces tools with almost-corded power. Working as an industrial electrician, I put my drills, sawzall and bandsaw to a LOT of use and was never left disappointed with the power output.
Despite the battery issue, I am still pretty sold on Milwaukee. Now, when it comes to an impact driver, my go-to is Makita. I have put it through its paces, abused the hell out of it, accidentally dropped it 25ft from a scissor lift onto concrete and its still going strong.
I used to say "friends don't let friends buy yellow tools", but have a few DeWalt tools that have yet to disappoint me, so I guess they are slowly growing on me, though I'm still pretty sold on Milwaukee and Makita.
