My mom wants an electric lawn mower. Any reccomendations?

Like any other tool- yes it does matter.

Manufacturing quality, design, features and ergonomics all matter.

I just went through a battery design/manufacturing issue with my 2 year old Skill brand 20v drill/osculating tool.
Both batteries failed within days. Again, one battery was 2 years old, the other newer.
The first one leaked thin, black tinted fluid.
I thought it had gotten wet, so cleaned it off, but it wouldn't charge.
This was right before the last hurricane, so I put the one I was currently using to put up plywood on the charger.
It never worked again.
I had to run an extension cord all over the place to finish my prep.

Those are $30 batteries.
I sure don't want to go through that with 48/56 volt batts.