I've got some good answers for you out of experience the last few years.
Own both a 40v Kobalt mower and also a Kobalt leaf blower. Before that I had a Toro gas mower and gas blower.
Battery Lawnmower:
Pros
-quiet
-light and manueverable
-ease (not getting gas, now pulling cords)
Cons
-battery life ( I have a pretty big yard and it's just enough to finish when it's not to high, if it's higher or taking longer it might die before finish)
-power (mine is 40v, maybe 60v is better, not as powerful as guess, the biggest negative there is the gas mower works like a vacuum, sucks up sticks pine cones,etc, I miss that)
Had it two years haven't changed any blades yet, still cuts fine.
Overall I prefer battery, it's just quiet and easy, grab and go.
The battery operated leaf blower is the best thing ever!! Plenty strong, very light. Can just grab and use it instead of sweeping, shoveling snow etc. Can even use indoors and mess with the kids etc. Love it.
If going battery stick with the same brand if getting more then one device. My mower and blower are both Kobalt and can use the batteries in either one, the mower is 5ah battery the blower is 3ah. Same physical size and charger. Having both batteries is a huge help.!