This game turned out to be exactly what I though it would be and that is a paradise for people who like to cause grief for other players. I didn't play the alpha so I decided to play solo first to learn the basics of the game. After a few minutes I finally figured out how to buy voyages and activate them in the ship. I'm studying the map when I hear voices from proximity chat. I look up to see a bigger ship come sailing in to the outpost. I thought a lone player who just started the game and has nothing would probably get left alone so I go back to looking at the map. Wrong, less than a minute latter I'm stabbed in the back while looking at the map. I then hear one player brag how they killed me while the other brags about stealing all my loot which apparently was just the cannon balls and bananas that came with the ship. I finally figure out how to get off the ghost ship and spawn back on my ship. I surprise one player still on my ship who jumps into the water and starts calling me expletives while screaming for help because I'm after after him. In reality I just went back to studying the map.
That was the only the first experience with other players. After that there was winking my ship while I was off and thus getting stranded on an island with a treasure chest and no way to turn it in. Then there was the outpost campers who ambushed and killed me while I was swimming to shore with a treasure chest.
Like I said, this was exactly what I was expecting from this game. Anytime you allow PVP with PVE you end up with grief. I've already seen threads calling for PVE only servers and or areas which ironically I disagree. My experience with PVP was frustrating to say the least but without PVP it would have been extremely boring. Anyway, that is my feedback from playing the beta so far.
Summary: Sea of Thieves is a Sea of Grief . . . solo players and new players beware.