I finally replaced my first-gen Ego 21" self-propelled with the latest model. I was an early adopter, so I think I got almost 10 years out of the first mower. I call that a win.
I bought the lowest priced self-propelled 21" model Ego. I didn't look into the two or three more expensive versions. At a glance, it looked like those models just have a longer run-time. Yeah, I don't need a longer run time! I only want some light exercise. I mow for a about 30 to 45 minutes. Then this old fat guy needs a cigar+water break in the shade.
I didn't realize how bad the old 7.5 AH battery had gotten. It just gradually ran shorter and shorter over the years. I didn't really notice until late last year. Eventually, I could only mow about 20 minutes between charges. Due to the near-constant rain this year, I could barely keep up with the growth. I was mowing every second it didn't rain. But what actually forced me to open my wallet and let out the moths was that the rear-drive died last week. I'm just too old to push-mow 14K SF.
The new battery (and mower) cut my entire 14K SF in one go. The battery status never went "red". It was a light cut at 3" HOC, but I was impressed. When I got a decent break in the rain, I was finally able to scalp the entire 14K from 3+" back down to 2" HOC. The battery status went to red after about 8K to 10K SF, so a recharge was needed. Again, I was impressed. The lawn is very dense and the mulching was very heavy. I had to re-sharpen the blade after than scalping.
From an engineer's view, the most interesting "old vs. new" comparison is the heavy-cut behavior. The first-gen model tended to increase to "max RPM mode" under very little load which drained the battery rather quickly. This behavior "trained" me to mow frequently and take very light cuts.
In contrast, the new model maintains the same RPM even under a fairly heavy load. I had to scalp rather heavy to invoke the "max RPM mode". I like this software change since the mower is quieter and the battery lasts much longer. Good job Ego.
My only thumbs-down for the new model is the rear drive-motor has a loud whine. I mean, the motor whine is significantly louder than the main motor (and blade) during normal mowing. I loathe the loud dentist drill sound that varies with the speed control. I'm very sensitive to high-pitch noises and it gets pretty darn annoying. The first-gen model had an absolutely silent rear drive-motor.
My old Ego mower and battery still work for about 20 min. For now, I'm just using it to hack down field weeds at my rear property line. But I'm thinking about converting it to a DIY hacked moss scrubber for my pavers on the North side of my house.