Electrek just ran a piece on top electric mopeds on the market right now, of course with Onyx really crushing it, and some other staples like the super73 and the new juiced scorpion, which I think has totally nailed the stepthru form and function of a moped as we've come to enjoy.
I built a cheapo electric moped last year, before reverting it to a much cheaper and far more powerful gas setup, and then used the bits to add a "hybrid" electric assist front wheel drive to a gas powered traditional moped.
I will admit, the gas ones give me much more trouble with reliability, especially with inclement (rainy) weather. I spent a lot of time waterproofing my daily rider sachs, making a special airbox and sealing all the electrics and it's still pretty uncomfortable in the rain, while the electric was solid rain shine or cold. It got slowere sooner in the coldest days, but I usually drive on the coldest days... also it's super easy to take the battery indoors.
I'm definitely still toying around with a few other e moped ideas.
that foldy sondors is a lot more "bicycle" but still looks fun: