Being a commercial mowing company, I am not sure Battery power is ready for our line of work. For a home Owner with a small sized lawn (up to 300 m≤) I think there is a place for these.
The reason I said that is to qualify my response as being relatively ill-informed.
Bosch is a quality company with great engineering so I would go with them.
It says there is 1,5 hours of life on that battery. I could use these units if I had about 8 sets of batteries.
If you do get one. Please post a follow up review. I am not familar with your Buffalo but if it is like ours, it is relatively thin and should not be too hard on the mower.