My wife and I bought two new Giant Ebikes in the summer of 2021. My wife bought the Roam E+ stagger frame and I chose the Giant Explore E+2.
The first problem we had was with the Roam. I managed to derail the chain off the front chainring whilst messing around with a lock. The chain dropped at the back of the chainring and steadfastly jammed itself between the chainring and the plastic motor cover. With your conventional bike you would just back pedal and feed the chain out. With an electric bike, back pedalling doesn't drive the chain. So the only option with a jam like this is to pedal forward, in effect jamming in the chain harder before it starts to lift out. During this process some damage is caused to the plastic cover.
Also, the problem here is you really need to place the bike on a workshop stand so you can drive the crank forward whilst lifting the chain out. Imagine this situation out on a ride, how on earth do you rectify it? A derailed chain off the chainring is rare in my experience, and more often occurs when a front mech is present (which is not the case on the Roam E+ or on my Explore E+2).
The lack of drive on back pedalling makes lubricating the chain tricky too, I just drive the chain by turning the chainwheel in reverse by hand.
My wife had her motor cover replaced and is happy leaving her bike in stock setup, but I was concerned about the jamming chain issue so I prevented any possibilty of it happening on my bike by switching the chainring and the chain guard. It's easily done, you don't even have to remove the crank.
See picture.
The chain can of course now potentially drop the other way toward the pedal but you have a much better chance of recovering this out on a ride. Again, I've never seen this happen outside of a poorly adjusted front mech. I've ridden many miles and my new arrangement has been flawless. Why doesn't Giant put a chain guard on the back of the chainring? Or pins on the chainring so a derailed chain can be just lifted out? I notice that you can buy a chain guide to prevent derailing which fits to the seat tube, mainly for mountain bikes that are hitting rough terrain and throwing the chain around. This only works for the forward rotation of the chain.
'Ah' you say, 'the pedals don't turn the chain backwards so there is no problem in reverse'. But there could be because the crank is driven backwards when you wheel your bike in reverse, like when manouevering on foot. Who knows, you could drop the chain.
My solution solves all the potential problems.