I've only used the mower 3 times (3 weeks in a row), so I will add/edit this review after more use if my opinion changes.I really like this mower but it’s only getting 3 stars because it was so damn difficult to do my pre-purchase research. One of the main reasons I use amazon is because of the extensive buyer reviews that allow me to thoroughly research before buying. There are hundreds of reviews on here that were about a different greenworks mower or simply a greenworks battery. I have included the picture of the mower I’m reviewing (the 40v brushless 21in with 2, 2.5ah batteries), so I hope this helps the reader to sort things out. I wanted to read about real experiences with this particular mower with those particular batteries, specifically about how long the batteries would last and how big of a yard it would cut on one charge...but it was near impossible to sort through the reviews for what I was looking for.With that being said, I have a little over a 1/3 of an acre and can get the job done when both batteries have a full charge. There is barely anything left on them when I’m done though, so there's no room for error or unexpected occurrences. I got a little less than 50 minutes of run time from both batteries. Full disclosure: I live in coastal NC and have patchy and thin grass (Centipede type grass). I don’t think I would have even seen a full 40 min of run time if I had thicker/fuller grass. However, it used to take me a little over an hour to cut the yard with my gas mower, and now it takes 45-50 minutes. This mower is so lightweight that I'm able to walk faster and I'm not getting as overheated or tiring so easily; so the job gets done faster.I can't yet comment on how long it takes the batteries to charge, because so far I've placed them on the charger and not paid close attention to the time when I'm busy with other chores.This is my first experience with any type of electric mower and I am now a big fan! It is so much easier to use, starts with the push of a button and I don't have to struggle with a pull cord. I would like a little more use from the batteries and may end up purchasing an additional battery next season to extend my run time.Pros:Easy to assemble, near fully assembled in the box; easy to start with the push of a button (NO MORE PULL CORD!!); extremely lightweight and easy to push; the mower is very quiet, about the same as an industrial fan, I'm looking forward to listening to a podcast next time I mow; the upright storage feature is a plus.Cons:Once the battery is in the mower, it's difficult to take out, especially when you're in the middle of yard work and have sweaty hands. The mower has a feature that automatically senses the need for more power...that should be a good thing. I have a very small patch of thick grass in my yard...when I start to cut this area, the motor starts working harder, but it seems to take really long time for it to adjust back to a normal speed and this may contribute to the battery depleting faster.Bottom line, the price was about the same I would have spent on a new gas mower, but if I end up buying another battery (probably will) it will end up being about $100 more expensive. In my opinion, the Pros of this mower outweigh the extra cost.