Is there a edge that the other one doesnt have?
It mostly comes down to user interface preferences.
Bitcoin Core allows more detailed control with RPC commands which make it more useful for programmers. It also is considered a "full node" meaning (among other things) that it contains the entire blockchain, and can supply it to new peers that are just starting up. Bitcoin Core provides some functionality for developers to create multi-sig transactions.
MultiBit is a bit more user friendly. It has more user interface features. It always sends the change from a transaction back to an address that you can see from the user interface (where Bitcoin Core would hide that address from you). It doesn't require as much disk space, because it doesn't store the full blockchain.
Both are open source software, and have existed or multiple years. They are both widely trusted. The fact that MultiBit re-uses existing addresses for change slightly reduces security and privacy, but not enough to be of concern to most people.
They are.
Other desktop bitcoin wallets that I'd suggest considering are:
Armory and Electrum.
It's a good idea to do some research and learn a bit about what each of the 4 most widely used desktop wallets has to offer. Then make the decision that's best for your personal needs.