Sugar beets were developed by Monsanto and KWS Saat but it was not crossed with anything else. It was created for easier sugar(Roundup Sugar). It is resistant to pesticides due to the mutations.
Pros: easier to farm, resistant to pesticides, has a higher sugar content than others.
Cons: not know of the long term effects, the pollen gets out and breeds with others making it a super plant, people could be allergic and eat something not knowing
I think that GMOs are a great thing. They have so many benefits that outweigh the downsides.