I bought that very Ego Electric mower shown above last year (only difference is that mine is the self-propelled version). It's awesome. The surprising thing is the power. I had a Toro 6.5 HP gas mower prior to this, and sometimes it actually struggled in mulching mode on my yard. I live on the Texas gulf coast, the only grass that grows reliably here is St. Augustine, which is really more of a weed than a grass. It's really thick and coarse, with tons of runners/stolons -- can be very difficult for any mower, especially in the summer when it grows fast and high.
The Ego actually performs better on my yard than the Toro did. When I get to a really thick spot, you could hear the Toro's governor give it maximum fuel, it would get louder, but would inevitably slow down the blade ... which ruins the mulching action, causes the clippings to build up under the deck, which makes it the problem worse.
The Ego will actually deliver MORE power and torque to the blade in those thick spots, and you hear the blade speed UP!
I'm careful with the battery charge on it ... I fully charge the battery right before I mow (their charger is a quick charger, takes 30-45 minutes for full charge on the 56V battery), and then I leave the battery in a partial discharge state between mowings. I'm over 1 year into ownership, no problems so far.
I have a smaller yard, only takes about 25 minutes to mow ... so I haven't run into any problems with run time. Typically the battery is slightly less than 50% when I'm done. I would estimate that the mower could easily run 45 minutes on a full charge, maybe a bit longer.
I also have the Ego line trimmer and the Ego clean-up/blower, both of which work awesome.